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  • 301.
    Chen, Qing
    et al.
    DESY, D-22607 Hamburg, Germany.;Univ Sci & Technol China, Sch Chem & Mat Sci, Hefei 230026, Peoples R China..
    Brett, Calvin
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. DESY, D-22607 Hamburg, Germany..
    Chumakov, Andrei
    DESY, D-22607 Hamburg, Germany..
    Gensch, Marc
    DESY, D-22607 Hamburg, Germany.;Tech Univ Munich, Phys Dept, Lehrstuhl Funkt Mat, D-85748 Garching, Germany..
    Schwartzkopf, Matthias
    DESY, D-22607 Hamburg, Germany..
    Koerstgens, Volker
    Tech Univ Munich, Phys Dept, Lehrstuhl Funkt Mat, D-85748 Garching, Germany..
    Söderberg, Daniel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Engineering Mechanics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fiberprocesser.
    Plech, Anton
    Karlsruhe Inst Technol KIT, Inst Photon Sci & Synchrotron Radiat, D-76021 Karlsruhe, Germany..
    Zhang, Peng
    Sun Yat Sen Univ, Sch Mat Sci & Engn, PCFM Lab, Guangzhou 510275, Peoples R China..
    Mueller-Buschbaum, Peter
    Tech Univ Munich, Phys Dept, Lehrstuhl Funkt Mat, D-85748 Garching, Germany.;Tech Univ Munich, Heinz Maier Leibniz Zentrum MLZ, D-85748 Garching, Germany..
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. DESY, D-22607 Hamburg, Germany..
    Layer-by-Layer Spray-Coating of Cellulose Nanofibrils and Silver Nanoparticles for Hydrophilic Interfaces2021In: ACS Applied Nano Materials, E-ISSN 2574-0970, Vol. 4, no 1, p. 503-513Article in journal (Refereed)
    Abstract [en]

    Silver nanoparticles (AgNPs) and AgNP-based composite materials have attracted growing interest due to their structure-dependent optical, electrical, catalytic, and stimuli-responsive properties. For practical applications, polymeric materials are often combined with AgNPs to provide flexibility and offer a scaffold for homogenous distribution of the AgNPs. However, the control over the assembly process of AgNPs on polymeric substrates remains a big challenge. Herein, we report the fabrication of AgNP/cellulose nanofibril (CNF) thin films via layer-by-layer (LBL) spray-coating. The morphology and self-assembly of AgNPs with increasing number of spray cycles are characterized by atomic force microscopy (AFM), grazing-incidence small-angle X-ray scattering (GISAXS), and grazing-incidence wide-angle X-ray scattering (GIWAXS). We deduce that an individual AgNP (radius = 15 +/- 3 nm) is composed of multiple nanocrystallites (diameter = 2.4 +/- 0.9 nm). Our results suggest that AgNPs are assembled into large agglomerates on SiO2 substrates during spray-coating, which is disadvantageous for AgNP functionalization. However, the incorporation of CNF substrates contributes to a more uniform distribution of AgNP agglomerates and individual AgNPs by its network structure and by absorbing the partially dissolved AgNP agglomerates. Furthermore, we demonstrate that the spray-coating of the AgNP/CNF mixture results in similar topography and agglomeration patterns of AgNPs compared to depositing AgNPs onto a precoated CNF thin film. Contact-angle measurements and UV/vis spectroscopy suggest that the deposition of AgNPs onto or within CNFs could increase the hydrophilicity of AgNP-containing surfaces and the localized surface plasmon resonance (LSPR) intensity of AgNP compared to AgNPs sprayed on SiO(2 )substrates, suggesting their potential applications in antifouling coatings or label-free biosensors. Thereby, our approach provides a platform for a facile and scalable production of AgNP/CNF films with a low agglomeration rate by two different methods as follows: (1) multistep layer-by-layer (LBL) spray-coating and (2) direct spray-coating of the AgNP/CNF mixture. We also demonstrate the ability of CNFs as a flexible framework for directing the uniform assembly of AgNPs with tailorable wettability and plasmonic properties.

  • 302.
    Chen, Tianyang
    et al.
    Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
    Banda, Harish
    Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
    Yang, Luming
    Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
    Li, Jian
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. Berzelii Center EXSELENT on Porous Materials, Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden.
    Zhang, Yugang
    Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, USA.
    Parenti, Riccardo
    Automobili Lamborghini S.p.A., 40019 Sant'Agata Bolognese, Italy.
    Dincă, Mircea
    Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
    High-rate, high-capacity electrochemical energy storage in hydrogen-bonded fused aromatics2023In: Joule, E-ISSN 2542-4351, Vol. 7, no 5, p. 986-1002Article in journal (Refereed)
    Abstract [en]

    Designing materials for electrochemical energy storage with short charging times and high charge capacities is a longstanding challenge. The fundamental difficulty lies in incorporating a high density of redox couples into a stable material that can efficiently conduct both ions and electrons. We report all-organic, fused aromatic materials that store up to 310 mAh g−1 and charge in as little as 33 s. This performance stems from abundant quinone/imine functionalities that decorate an extended aromatic backbone, act as redox-active sites, engage in hydrogen bonding, and enable a delocalized high-rate energy storage with stability upon cycling. The extended conjugation and hydrogen-bonding-assisted bulk charge storage contrast with the surface-confined or hydration-dependent behavior of traditional inorganic electrodes.

  • 303.
    Chen, Tianyang
    et al.
    MIT, Dept Chem, Cambridge, MA 02139 USA..
    Dou, Jin-Hu
    MIT, Dept Chem, Cambridge, MA 02139 USA..
    Yang, Luming
    MIT, Dept Chem, Cambridge, MA 02139 USA..
    Sun, Chenyue
    MIT, Dept Chem, Cambridge, MA 02139 USA..
    Oppenheim, Julius J.
    MIT, Dept Chem, Cambridge, MA 02139 USA..
    Li, Jian
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. Stockholm Univ, Berzelii Ctr EXSELENT Porous Mat, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden..
    Dinca, Mircea
    MIT, Dept Chem, Cambridge, MA 02139 USA..
    Dimensionality Modulates Electrical Conductivity in Compositionally Constant One-, Two-, and Three-Dimensional Frameworks2022In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 144, no 12, p. 5583-5593Article in journal (Refereed)
    Abstract [en]

    We reveal here the construction of Ni-based metal-organic frameworks (MOFs) and conjugated coordination polymers (CCPs) with different structural dimensionalities, including closely pi-stacked 1D chains (Ni-1D), aggregated 2D layers (Ni-2D), and a 3D framework (Ni-3D), based on 2,3,5,6-tetraamino-1,4-hydroquinone (TAHQ) and its various oxidized forms. These materials have the same metal-ligand composition but exhibit distinct electronic properties caused by different dimensionalities and supramolecular interactions between SBUs, ligands, and structural motifs. The electrical conductivity of these materials spans nearly 8 orders of magnitude, approaching 0.3 S/cm.

  • 304. Chen, W.
    et al.
    Guo, R.
    Tang, H.
    Wienhold, K. S.
    Li, N.
    Jiang, Z.
    Tang, J.
    Jiang, X.
    Kreuzer, L. P.
    Liu, H.
    Schwartzkopf, M.
    Sun, X. W.
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany.
    Wang, K.
    Xu, B.
    Müller-Buschbaum, P.
    Operando structure degradation study of PbS quantum dot solar cells2021In: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 14, no 6, p. 3420-3429Article in journal (Refereed)
    Abstract [en]

    PbS quantum dot (QD) solar cells demonstrate great potential in solar energy conversion with a broad and flexible spectral response. Even though long-term storage stabilities of QD solar cells were reported in literature, the operation stability from a more practical aspect, to date, has been not yet investigated. Herein, we observe the structure degradation process of a PbS QD-ink based solar cell during the device operation. Simultaneously to probing the solar cell parameters, the overall structure evolutions of the QDs in both, active layer and hole transport layer of the solar cell are studied with grazing-incidence small- and wide-angle X-ray scattering (GISAXS/GIWAXS). We find a spontaneous decrease of the QD inter-dot distance with an increase in the spatial disorder in the active layer (PbX2-PbS QDs, X = I, and Br) during the operation induced degradation. Consequently, the structure disorder-induced broadening of the energy state distribution is responsible for the decrease in open-circuit voltageVocleading to the device degradation. These findings elucidate the origin of light-soaking as well as the structure degradation of QD ink-based solar cells and indicate that the stability of the device can be realized by the positional stabilization of the QDs in the QD solid.

  • 305.
    Chen, Wei
    et al.
    Physik Department, Lehrstuhl für Funktionelle Materialien, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany.
    Liang, Suzhe
    Physik Department, Lehrstuhl für Funktionelle Materialien, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany.
    Löhrer, Franziska C.
    Physik Department, Lehrstuhl für Funktionelle Materialien, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany.
    Schaper, Simon J.
    Physik Department, Lehrstuhl für Funktionelle Materialien, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany.
    Li, Nian
    Physik Department, Lehrstuhl für Funktionelle Materialien, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany.
    Cao, Wei
    Physik Department, Lehrstuhl für Funktionelle Materialien, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany.
    Kreuzer, Lucas P.
    Physik Department, Lehrstuhl für Funktionelle Materialien, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany.
    Liu, Haochen
    Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Xueyuan Blvd. 1088, 518055 Shenzhen, China.
    Tang, Haodong
    Körstgens, Völker
    Physik Department, Lehrstuhl für Funktionelle Materialien, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany.
    Schwartzkopf, Matthias
    Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany.
    Wang, Kai
    Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Xueyuan Blvd. 1088, 518055 Shenzhen, China.
    Sun, X. W.
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Müller-Buschbaum, P.
    In situ Grazing-Incidence Small-Angle X-ray Scattering Observation of Gold Sputter Deposition on a PbS Quantum Dot Solid2020In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 12, no 41, p. 46942-46952Article in journal (Refereed)
    Abstract [en]

    For PbS quantum dot (QD)-based optoelectronic devices, gold is the most frequently used electrode material. In most device architectures, gold is in direct contact with the QD solid. To better understand the formation of the interface between gold and a close-packed QD layer at an early stage, in situ grazing-incidence small-angle X-ray scattering is used to observe the gold sputter deposition on a 1,2-ethanedithiol (EDT)-treated PbS QD solid. In the kinetics of gold layer growth, the forming and merging of small gold clusters (radius less than 1.6 nm) are observed at the early stages. The thereby formed medium gold clusters (radius between 1.9-2.4 nm) are influenced by the QDs' templating effect. Furthermore, simulations suggest that the medium gold clusters grow preferably along the QDs' boundaries rather than as a top coating of the QDs. When the thickness of the sputtered gold layer reaches 6.25 nm, larger gold clusters with a radius of 5.3 nm form. Simultaneously, a percolation layer with a thickness of 2.5 nm is established underneath the gold clusters. This fundamental understanding of the QD-gold interface formation will help to control the implementation of sputtered gold electrodes on close-packed QD solids in device manufacturing processes.

  • 306.
    Chen, Wei
    et al.
    Tech Univ Munich, Lehrstuhl Funkt Mat, Phys Dept, James Franck Str 1, D-85748 Garching, Germany..
    Tang, Haodong
    Southern Univ Sci & Technol SUSTech, Dept Elect & Elect Engn, Xueyuan Blvd 1088, Shenzhen 518055, Peoples R China..
    Li, Nian
    Tech Univ Munich, Lehrstuhl Funkt Mat, Phys Dept, James Franck Str 1, D-85748 Garching, Germany..
    Scheel, Manuel A.
    Southern Univ Sci & Technol SUSTech, Dept Elect & Elect Engn, Xueyuan Blvd 1088, Shenzhen 518055, Peoples R China..
    Xie, Yue
    Southern Univ Sci & Technol SUSTech, Dept Elect & Elect Engn, Xueyuan Blvd 1088, Shenzhen 518055, Peoples R China..
    Li, Depeng
    Tech Univ Munich, Lehrstuhl Funkt Mat, Phys Dept, James Franck Str 1, D-85748 Garching, Germany..
    Koerstgens, Volker
    DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Schwartzkopf, Matthias
    Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany.
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany.
    Wang, Kai
    Southern Univ Sci & Technol SUSTech, Dept Elect & Elect Engn, Xueyuan Blvd 1088, Shenzhen 518055, Peoples R China..
    Sun, Xiao Wei
    Southern Univ Sci & Technol SUSTech, Dept Elect & Elect Engn, Xueyuan Blvd 1088, Shenzhen 518055, Peoples R China..
    Mueller-Buschbaum, Peter
    Tech Univ Munich, Lehrstuhl Funkt Mat, Phys Dept, James Franck Str 1, D-85748 Garching, Germany.;Tech Univ Munich, Heinz Maier Leibnitz Zentrum MLZ, Lichtenbergstr 1, D-85748 Garching, Germany..
    Colloidal PbS quantum dot stacking kinetics during deposition via printing2020In: Nanoscale Horizons, ISSN 2055-6764, E-ISSN 2055-6756, Vol. 5, no 5, p. 880-885Article in journal (Refereed)
    Abstract [en]

    Colloidal PbS quantum dots (QDs) are attractive for solution-processed thin-film optoelectronic applications. In particular, directly achieving QD thin-films by printing is a very promising method for low-cost and large-scale fabrication. The kinetics of QD particles during the deposition process play an important role in the QD film quality and their respective optoelectronic performance. In this work, the particle self-organization behavior of small-sized QDs with an average diameter of 2.88 +/- 0.36 nm is investigated for the first time in situ during printing by grazing-incidence small-angle X-ray scattering (GISAXS). The time-dependent changes in peak intensities suggest that the structure formation and phase transition of QD films happen within 30 seconds. The stacking of QDs is initialized by a templating effect, and a face-centered cubic (FCC) film forms in which a superlattice distortion is also found. A body-centered cubic nested FCC stacking is the final QD assembly layout. The small size of the inorganic QDs and the ligand collapse during the solvent evaporation can well explain this stacking behavior. These results provide important fundamental understanding of structure formation of small-sized QD based films prepared via large-scale deposition with printing with a slot die coater.

  • 307.
    Chen, Yangyang
    et al.
    Guangxi Univ, Coll Light Ind & Food Engn, Nanning 530004, Peoples R China.;Guangxi Key Lab Clean Pulp & Papermaking & Pollut, Nanning 530004, Peoples R China..
    Hou, Hewei
    Guangxi Univ, Coll Light Ind & Food Engn, Nanning 530004, Peoples R China.;Guangxi Key Lab Clean Pulp & Papermaking & Pollut, Nanning 530004, Peoples R China..
    Liu, Bing
    Guangxi Univ, Coll Light Ind & Food Engn, Nanning 530004, Peoples R China.;Guangxi Key Lab Clean Pulp & Papermaking & Pollut, Nanning 530004, Peoples R China..
    Li, Moyang
    Guangxi Univ, Coll Light Ind & Food Engn, Nanning 530004, Peoples R China.;Guangxi Key Lab Clean Pulp & Papermaking & Pollut, Nanning 530004, Peoples R China..
    Chen, Lan
    Guangxi Univ, Coll Light Ind & Food Engn, Nanning 530004, Peoples R China.;Guangxi Key Lab Clean Pulp & Papermaking & Pollut, Nanning 530004, Peoples R China..
    Chen, Changzhou
    Guangxi Univ, Coll Light Ind & Food Engn, Nanning 530004, Peoples R China.;Guangxi Key Lab Clean Pulp & Papermaking & Pollut, Nanning 530004, Peoples R China..
    Wang, Shuangfei
    Guangxi Univ, Coll Light Ind & Food Engn, Nanning 530004, Peoples R China.;Guangxi Key Lab Clean Pulp & Papermaking & Pollut, Nanning 530004, Peoples R China..
    Li, Yuanyuan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. Guangxi Univ, Coll Light Ind & Food Engn, Nanning 530004, Peoples R China..
    Min, Douyong
    Guangxi Univ, Coll Light Ind & Food Engn, Nanning 530004, Peoples R China.;Guangxi Key Lab Clean Pulp & Papermaking & Pollut, Nanning 530004, Peoples R China..
    Wood-derived scaffolds decorating with nickel cobalt phosphate nanosheets and carbon nanotubes used as monolithic electrodes for assembling high-performance asymmetric supercapacitor2023In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 454, article id 140453Article in journal (Refereed)
    Abstract [en]

    Lightweight carbonized wood (CW) loaded with pseudocapacitive materials has demonstrated excellent energy density. However, the direct loading of active materials usually results in poor rate performance and cycling stability. Herein, we fabricated a CW electrode with high loading of active materials and conductivity through chemical vapor deposition (CVD) and electrodeposition to sequentially incorporate carbon nanotubes (CNTs) and nickel-cobalt phosphate (NiCo-P) nanosheets. This integrated NiCo-P/CNT/CW electrode exhibited a promising areal capacitance of 11.2F cm-2 at a current density of 10 mA cm-2, and a notable capacitance retention rate of 86.6 % at 60 mA cm-2. The asymmetric supercapacitor (ASC) device assembled with the prepared electrode as anode and the self-activated carbonized wood (SCW) electrode as cathode delivers outstanding energy density of 5.74 mWh cm-3 (12.1 Wh kg -1) at power density of 18.75 mW cm-3 (39.5 W kg -1) while maintaining a high capacitance retention of 92.4 % after 10,000 charge-discharge cycles. This work provides an advanced approach for constructing supercapacitors with remarkable energy density and rate performance from the natural wood derived electrodes.

  • 308.
    Chen, Yu
    et al.
    Beijing Inst Technol, Sch Mat Sci & Engn, Beijing Engn Res Ctr Cellulose & Its Derivat, Beijing 100081, Peoples R China..
    Nishiyama, Yoshiharu
    Univ Grenoble Alpes, CNRS, CERMAV, F-38000 Grenoble, France..
    Lu, Ang
    Wuhan Univ, Coll Chem & Mol Sci, Wuhan 430072, Peoples R China..
    Fang, Yan
    Fujian Normal Univ, Coll Chem & Mat Sci, Fujian Key Lab Polymer Mat, Fujian 350007, Peoples R China..
    Shao, Ziqiang
    Beijing Inst Technol, Sch Mat Sci & Engn, Beijing Engn Res Ctr Cellulose & Its Derivat, Beijing 100081, Peoples R China..
    Hu, Tao
    Shanghai Univ, Sch Mat Sci & Engn, State Key Lab Adv Special Steels, Shanghai 200444, Peoples R China..
    Ye, Dongdong
    Wuyi Univ, Sch Text Mat & Engn, Jiangmen 529020, Peoples R China..
    Qi, Haisong
    South China Univ Technol, State Key Lab Pulp & Paper Engn, Guangzhou 510640, Peoples R China..
    Li, Xiaodong
    Beijing Inst Technol, Sch Mat Sci & Engn, Beijing 100081, Peoples R China..
    Wohlert, Jakob
    KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Chen, Pan
    Beijing Inst Technol, Sch Mat Sci & Engn, Beijing Engn Res Ctr Cellulose & Its Derivat, Beijing 100081, Peoples R China..
    The thermodynamics of enhanced dope stability of cellulose solution in NaOH solution by urea2023In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 311, p. 120744-, article id 120744Article in journal (Refereed)
    Abstract [en]

    The addition of urea in pre-cooled alkali aqueous solution is known to improve the dope stability of cellulose solution. However, its thermodynamic mechanism at a molecular level is not fully understood yet. By using molecular dynamics simulation of an aqueous NaOH/urea/cellulose system using an empirical force field, we found that urea was concentrated in the first solvation shell of the cellulose chain stabilized mainly by dispersion interaction. When adding a glucan chain into the solution, the total solvent entropy reduction is smaller if urea is present. Each urea molecule expelled an average of 2.3 water molecules away from the cellulose surface, releasing water entropy that over-compensates the entropy loss of urea and thus maximizing the total entropy. Scaling the Lennard-Jones parameter and atomistic partial charge of urea revealed that direct urea/cellulose interaction was also driven by dispersion energy. The mixing of urea solution and cellulose solution in the presence or absence of NaOH are both exothermic even after correcting for the contribution from dilution.

  • 309.
    Chen, Yujie
    et al.
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Chen, Chi
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Rehman, Hafeez Ur
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Zheng, Xu
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Li, Hua
    Shanghai Jiao Tong Univ, Collaborat Innovat Ctr Adv Ship & Dee Sea Explora, Shanghai 200240, Peoples R China..
    Liu, Hezhou
    Shanghai Jiao Tong Univ, Collaborat Innovat Ctr Adv Ship & Dee Sea Explora, Shanghai 200240, Peoples R China..
    Hedenqvist, Mikael S.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Shape-Memory Polymeric Artificial Muscles: Mechanisms, Applications and Challenges2020In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 25, no 18, article id 4246Article, review/survey (Refereed)
    Abstract [en]

    Shape-memory materials are smart materials that can remember an original shape and return to their unique state from a deformed secondary shape in the presence of an appropriate stimulus. This property allows these materials to be used as shape-memory artificial muscles, which form a subclass of artificial muscles. The shape-memory artificial muscles are fabricated from shape-memory polymers (SMPs) by twist insertion, shape fixation via T(m)or T-g, or by liquid crystal elastomers (LCEs). The prepared SMP artificial muscles can be used in a wide range of applications, from biomimetic and soft robotics to actuators, because they can be operated without sophisticated linkage design and can achieve complex final shapes. Recently, significant achievements have been made in fabrication, modelling, and manipulation of SMP-based artificial muscles. This paper presents a review of the recent progress in shape-memory polymer-based artificial muscles. Here we focus on the mechanisms of SMPs, applications of SMPs as artificial muscles, and the challenges they face concerning actuation. While shape-memory behavior has been demonstrated in several stimulated environments, our focus is on thermal-, photo-, and electrical-actuated SMP artificial muscles.

  • 310.
    Chen, Yujie
    et al.
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Chen, Zhen
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Chen, Chi
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Rehman, Hafeez Ur
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Liu, Hezhou
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Li, Hua
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Hedenqvist, Mikael S.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymeric Materials.
    A gradient-distributed liquid-metal hydrogel capable of tunable actuation2021In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 421, p. 127762-, article id 127762Article in journal (Refereed)
    Abstract [en]

    Although thermoresponsive hydrogels have numerous applications that range from soft robots, biomedical engineering, and actuators to sensors for artificial muscles, the existing hydrogel actuators undergo only unidirectional deformation under a single thermal stimulus and suffer from slow actuation and unstable interfacial adhesion in multiple layers. Herein, hydrogels containing gradient-distributed polydopamine-coated eutectic gallium-indium (PDA-EGaIn) nanodroplets in a poly(N-isopropylacrylamide) (PNIPAM) matrix and thus featuring a gradient distribution of thermal conductivity and an increased barrier towards water loss are shown to be capable of a rapid and tuneable thermoresponse. Notably, whereas hydrogels with a low content of PDAEGaIn undergo rapid one-way bending under a single thermal (45 degrees C) stimulus, those with a high content of PDAEGaIn undergo sequential bidirectional (bending) actuation. The ability of these hydrogels to undergo fast and tuneable actuation under a single thermal stimulus makes them suitable for use in grab-release instruments and soft robots.

  • 311.
    Chen, Zhen
    et al.
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Chen, Yujie
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Hedenqvist, Mikael S.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymeric Materials.
    Chen, Chi
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Cai, Chao
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Li, Hua
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Liu, Hezhou
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Fu, Jun
    Sun Yat Sen Univ, Minist Educ, Sch Mat Sci & Engn, Key Lab Polymer Composite & Funct Mat, 135 Xingang Rd West, Guangzhou 510275, Peoples R China..
    Multifunctional conductive hydrogels and their applications as smart wearable devices2021In: Journal of materials chemistry. B, ISSN 2050-750X, E-ISSN 2050-7518, Vol. 9, no 11, p. 2561-2583Article, review/survey (Refereed)
    Abstract [en]

    Recently, hydrogekbased conductive materials and their applications as smart wearable devices have been paid tremendous attention due to their high stretchability, flexibility, and excellent biocompatibility. Compared with single functional conductive hydrogels, multifunctional conductive hydrogels are more advantageous to match various demands for practical applications. This review focuses on multifunctional conductive hydrogels applied for smart wearable devices. Representative strategies for conduction of hydrogels are discussed firstly: (1) electronic conduction based on the conductive fillers and (2) ionic conduction based on charged ions. Then, the common and intensive research on multiple functionahties of conductive hydrogels, such as mechanical properties, conductive and sensory properties, anti-freezing and moisturizing properties, and adhesion and self-healing properties is presented. The applications of multifunctional conductive hydrogels such as in human motion sensors, sensory skins, and personal healthcare diagnosis are provided in the third part. Finally, we offer our perspective on open challenges and future areas of interest for multifunctional conductive hydrogels used as smart wearable devices.

  • 312.
    Chernova, E. A.
    et al.
    Lomonosov Moscow State Univ, Dept Mat Sci, 1-73 Leninskiye Gory, Moscow 119991, Russia..
    Petukhov, D. I.
    Lomonosov Moscow State Univ, Dept Mat Sci, 1-73 Leninskiye Gory, Moscow 119991, Russia.;Lomonosov Moscow State Univ, Dept Chem, 1-3 Leninskiye Gory, Moscow 119991, Russia..
    Chumakov, A. P.
    DESY Deutsch Elekt Synchrotron, Notkestr 85, D-22607 Hamburg, Germany..
    Kirianova, A. V.
    Lomonosov Moscow State Univ, Dept Mat Sci, 1-73 Leninskiye Gory, Moscow 119991, Russia..
    Sadilov, I. S.
    Lomonosov Moscow State Univ, Dept Mat Sci, 1-73 Leninskiye Gory, Moscow 119991, Russia..
    Kapitanova, O. O.
    Lomonosov Moscow State Univ, Dept Chem, 1-3 Leninskiye Gory, Moscow 119991, Russia..
    Boytsova, O. V.
    Lomonosov Moscow State Univ, Dept Mat Sci, 1-73 Leninskiye Gory, Moscow 119991, Russia.;RAS, Kurnakov Inst Gen & Inorgan Chem, Leninsky Ave 31, Moscow 119991, Russia..
    Valeev, R. G.
    Russian Acad Sci UdmFRC UB RAS, Udmurt Fed Res Ctr, Ural Brunch, St Them Tatiana Baramzina 34, Izhevsk 426067, Russia..
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. DESY Deutsch Elekt Synchrotron, Notkestr 85, D-22607 Hamburg, Germany..
    Eliseev, Ar A.
    Lomonosov Moscow State Univ, Dept Chem, 1-3 Leninskiye Gory, Moscow 119991, Russia..
    Eliseev, An A.
    Lomonosov Moscow State Univ, Dept Mat Sci, 1-73 Leninskiye Gory, Moscow 119991, Russia..
    The role of oxidation level in mass-transport properties and dehumidification performance of graphene oxide membranes2021In: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 183, p. 404-414Article in journal (Refereed)
    Abstract [en]

    Here we report on gas and vapor transport properties of ultra-thin graphene oxide (GO) membranes, with various C:O ratios. Graphene oxide nanosheets with an average lateral size of 800 nm and C:O ratio ranging from 2.11 to 1.81 have been obtained using improved Hummers' method by variation of graphite:KMnO4 ratio. Thin-film selective layers based on the obtained graphene oxide have been spin-coated onto porous substrates. To extend the C:O range to 2.60, thermal reduction of GO membranes was applied. A decrease in C:O ratio leads to significant water vapor permeance growth to over 60 m(3)(STP).m(-2).bar(-1).h(-1) while the permeance towards permanent gases reduces slightly. According to the permeation and sorption measurements, a decisive role of H2O diffusivity has been established, while the water sorption capacity of the graphene oxide stays nearly independent of C:O ratio in GO. The result is supported by semi-empirical modeling which reveals diminution of H2O jump activation barriers with both increasing GO interlayer spacing and its oxidation degree. The height of the activation barriers was found to vary up to an order of magnitude within the entire range of relative humidity (0-100% RH), lowering significantly for strongly oxidized GO. Our results evidence the necessity of attaining maximum GO oxidation degree for improving water transport in GO, especially at low partial pressures.

  • 313. Cho, I.
    et al.
    Prier, C. K.
    Jia, Z. -J
    Zhang, R. K.
    Görbe, Tamás
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Arnold, F. H.
    Enantioselective Aminohydroxylation of Styrenyl Olefins Catalyzed by an Engineered Hemoprotein2019In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 58, no 10, p. 3138-3142Article in journal (Refereed)
    Abstract [en]

    Chiral 1,2-amino alcohols are widely represented in biologically active compounds from neurotransmitters to antivirals. While many synthetic methods have been developed for accessing amino alcohols, the direct aminohydroxylation of alkenes to unprotected, enantioenriched amino alcohols remains a challenge. Using directed evolution, we have engineered a hemoprotein biocatalyst based on a thermostable cytochrome c that directly transforms alkenes to amino alcohols with high enantioselectivity (up to 2500 TTN and 90 % ee) under anaerobic conditions with O-pivaloylhydroxylamine as an aminating reagent. The reaction is proposed to proceed via a reactive iron-nitrogen species generated in the enzyme active site, enabling tuning of the catalyst's activity and selectivity by protein engineering.

  • 314.
    Cho, Sung-Woo
    et al.
    KTH.
    Hedenqvist, Mikael S.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    CELL 175-Evaluation of heat sealability of wheat gluten films2008In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 235Article in journal (Other academic)
  • 315.
    Chondrogiannis, Georgios
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. KTH Royal Institute of Technology.
    Sample-to-answer paper-based nucleic acid amplification tests2022Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Nucleic Acid Amplification Tests (NAATs) with PCR technology to amplify DNA, are the golden standard for infectious disease diagnostics, but they require benchtop instruments and trained users to be performed. For this reason, we all had to send PCR test to centralized laboratories during the Covid-19 pandemic. A year into the pandemic, home-based antigen paper-based tests became available for Covid, but these were not as sensitive, so PCR tests had to be used still. This development emphasized the need for technologies that enable NAATs with superior sensitivity to be performed at home. There are three technological advanced that could make such tests possible: 1)  Paper based devices, called paper microfluidics, have been developed to enable more advanced steps of testing without laboratory equipment. These paper-based system incorporate advanced functionality and multiple reaction steps. 2) New DNA amplification techniques, called isothermal amplification, have been developed which, contrary to PCR, can be run without a thermocycler, enabling DNA amplification to be carried out even inside a paper.  3) Several methods to detect DNA have been shown using paper.

    One step that is still largely unsolved in NAATs is the sample preparation step, hindering the development of fully paper-based NAATs. In sample preparation, nucleic acids are extracted from bacteria or virus, usually using reagents harmful to DNA amplification. These steps are thereofore complicated and require several washing steps and heating, and are therefore difficult to integrate into paper.

    In this thesis, we used a simple, cost-effective, and scalable method to incorporate sample preparation in paper, thus taking NAATs towards point of care. We solve this problem by immobilizing enzymes that are used for sample preparation on nitrocellulose paper. The immobilized enzymes remain functional and can be used for biochemical reactions, while they are strongly bound to the paper. This method enables the separation of these enzymes from the sample, protecting downstream sensitive reactions of DNA amplification and eliminates the need for high temperature deactivation or washing steps. Specifically, we show that the enzyme achromopeptidase can do cell lysis from the Staphylococcus epidermidis bacteria, a common pathogenic gram-positive bacterium, and use its DNA in further reaction to perform a sample-to-answer paper-based NAAT. These NAATs employed a low temperature amplification step called Recombinase Polymerase Amplification (RPA) and DNA detection with a lateral flow strip.

    We further show the enzyme proteinase K, also immobilized on paper, can digest RNase in saliva samples, an enzyme that breaks down RNA leading to false-negative results. This results enabled an easy sample preparation step towards saliva viral DNA self-testing.

    Finally, in this work we developed a paper microfluidic system that can carry out an enzyme-linked oligonucleotide assay, which demonstrated much higher sensitivity in detecting amplified DNA than conventional lateral flow assays. In summary, these results provide solutions towards high-performing, affordable and instrument-free paper-based NAATs home-testing.

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  • 316.
    Chondrogiannis, Georgios
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Khaliliazar, Shirin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Toldrà Filella, Anna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Reu, Pedro
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Hamedi, Mahiar
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Nitrocellulose-bound achromopeptidase for point-of-care nucleic acid tests2021In: Scientific Reports, E-ISSN 2045-2322, Vol. 11, no 1, article id 6140Article in journal (Refereed)
    Abstract [en]

    Enzymes are the cornerstone of modern biotechnology. Achromopeptidase (ACP) is a well-known enzyme that hydrolyzes a number of proteins, notably proteins on the surface of Gram-positive bacteria. It is therefore used for sample preparation in nucleic acid tests. However, ACP inhibits DNA amplification which makes its integration difficult. Heat is commonly used to inactivate ACP, but it can be challenging to integrate heating into point-of-care devices. Here, we use recombinase polymerase amplification (RPA) together with ACP, and show that when ACP is immobilized on nitrocellulose paper, it retains its enzymatic function and can easily and rapidly be activated using agitation. The nitrocellulose-bound ACP does, however, not leak into the solution, preventing the need for deactivation through heat or by other means. Nitrocellulose-bound ACP thus opens new possibilities for paper-based Point-of-Care (POC) devices.

  • 317.
    Chondrogiannis, Georgios
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Reu, Pedro
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Hamedi, Mahiar
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Paper-Based Bacterial Lysis Enables Sample-to-Answer Home-based DNA Testing2023In: Advanced Materials Technologies, E-ISSN 2365-709X, Vol. 8, no 4, p. 2201004-, article id 2201004Article in journal (Refereed)
    Abstract [en]

    Nucleic acid amplification testing (NAAT) is the gold standard for infectious disease diagnostics. Currently NAATs are mainly limited to centralized laboratories, while paper-based antigen tests are used for rapid home-based diagnostics. DNA extraction, the initial sample preparation step in NAATs, remains a bottleneck that hinders its development toward home-based kits. This step requires the use of compounds detrimental to the enzymes in downstream DNA amplification. Here, this work overcomes this bottleneck by immobilizing the enzyme achromopeptidase (ACP) on nitrocellulose, to both store and enable the separation of the enzymes from the other steps. This work provides proof-of-concept that immobilized ACP is effective at lysis and release of amplifiable DNA from gram-positive Staphylococcus epidermidis and enables the use of the lysate directly for DNA amplification, without the need for heat deactivation of the enzyme. This sample preparation method requires only incubation at 37 °C and mild agitation, which allows to implement it with fully disposable and affordable equipment. Consequently, this work enables to combine the paper-based DNA extraction method with the isothermal recombinase polymerase amplification (RPA) followed by lateral flow detection to demonstrate a sample-to-answer NAAT packaged as an instrument free self-test kit expanding the capabilities of home-testing beyond antigen tests. 

  • 318.
    Chondrogiannis, Georgios
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Reu, Pedro
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Hamedi, Mahiar
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Paper‐Based Bacterial Lysis Enables Sample‐to‐Answer Home‐based DNATestingManuscript (preprint) (Other academic)
  • 319.
    Chondrogiannis, Georgios
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Toldrà Filella, Anna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Hanze, Martin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Paper‐based RNase digestion towards viral nucleic acid self‐testsManuscript (preprint) (Other academic)
  • 320.
    Choong, Ferdinand
    et al.
    Karolinska Inst, AIMES Ctr Adv Integrated Med & Engn Sci, Stockholm, Sweden.;KTH Royal Inst Technol, Stockholm, Sweden.;Karolinska Inst, Dept Neurosci, Stockholm, Sweden..
    Huzell, Smilla
    Karolinska Inst, AIMES Ctr Adv Integrated Med & Engn Sci, Stockholm, Sweden.;KTH Royal Inst Technol, Stockholm, Sweden.;Karolinska Inst, Dept Neurosci, Stockholm, Sweden.;Ebba Biotech AB, Stockholm, Sweden..
    Rosenberg, Ming
    Karolinska Inst, AIMES Ctr Adv Integrated Med & Engn Sci, Stockholm, Sweden.;KTH Royal Inst Technol, Stockholm, Sweden.;Karolinska Inst, Dept Neurosci, Stockholm, Sweden..
    Eckert, Johannes
    Karolinska Inst, AIMES Ctr Adv Integrated Med & Engn Sci, Stockholm, Sweden.;KTH Royal Inst Technol, Stockholm, Sweden.;Karolinska Inst, Dept Neurosci, Stockholm, Sweden.;Swiss Fed Inst Technol, Dept Biol, Zurich, Switzerland..
    Nagaraj, Madhu
    Aarhus Univ, iNANO, Aarhus, Denmark.;Aarhus Univ, Dept Mol Biol & Genet, Aarhus, Denmark..
    Zhang, Tianqi
    Karolinska Inst, AIMES Ctr Adv Integrated Med & Engn Sci, Stockholm, Sweden.;KTH Royal Inst Technol, Stockholm, Sweden.;Karolinska Inst, Dept Neurosci, Stockholm, Sweden..
    Melican, Keira
    Karolinska Inst, AIMES Ctr Adv Integrated Med & Engn Sci, Stockholm, Sweden.;KTH Royal Inst Technol, Stockholm, Sweden.;Karolinska Inst, Dept Neurosci, Stockholm, Sweden..
    Otzen, Daniel E.
    Aarhus Univ, iNANO, Aarhus, Denmark.;Aarhus Univ, Dept Mol Biol & Genet, Aarhus, Denmark..
    Richter-Dahlfors, Agneta
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. Karolinska Inst, AIMES Ctr Adv Integrated Med & Engn Sci, Stockholm, Sweden.;KTH Royal Inst Technol, Stockholm, Sweden.;Karolinska Inst, Dept Neurosci, Stockholm, Sweden..
    A semi high-throughput method for real-time monitoring of curli producing Salmonella biofilms on air-solid interfaces2021In: Biofilm, E-ISSN 2590-2075, Vol. 3, p. 100060-, article id 100060Article in journal (Refereed)
    Abstract [en]

    Biofilms enable bacteria to colonize numerous ecological niches. Bacteria within a biofilm are protected by the extracellular matrix (ECM), of which the fibril-forming amyloid protein curli and polysaccharide cellulose are major components in members of Salmonella, Eschericha and Mycobacterium genus. A shortage of real-time detection methods has limited our understanding of how ECM production contributes to biofilm formation and pathogenicity. Here we present optotracing as a new semi-high throughput method for dynamic monitoring of Salmonella biofilm growth on air-solid interfaces. We show how an optotracer with binding-induced fluorescence acts as a dynamic fluorescent reporter of curli expression during biofilm formation on agar. Using spectrophotometry and microscopic imaging of fluorescence, we analyse in real-time the development of the curli architecture in relation to bacterial cells. With exceptional spatial and temporal precision, this revealed a well-structured, non-uniform distribution of curli organised in distally projecting radial channel patterns. Dynamic monitoring of the biofilm also showed defined regions undergoing different growth phases. ECM structures were found to assemble in regions of late exponential growth phase, suggesting that ECM forms on site after bacteria colonize the surface. As the optotracer biofilm method expedites screening of curli production, providing exceptional spatial-temporal understanding of the surface-associated biofilm lifestyle, this method adds a new technique to further our understanding of bacterial biofilms.

  • 321.
    Choong, Ferdinand X.
    et al.
    Swedish Medical Nanoscience Center, Department of Neuroscience Karolinska Institutet, Stockholm, Sweden.
    Lantz, Linda
    Department of Chemistry IFM, Linköping University, Linköping, Sweden.
    Shirani, Hamid
    Department of Chemistry IFM, Linköping University, Linköping, Sweden.
    Schulz, Anette
    Swedish Medical Nanoscience Center, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
    Nilsson, K. Peter R.
    Department of Chemistry IFM, Linköping University, Linköping, Sweden.
    Edlund, Ulrica
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Richter-Dahlfors, Agneta
    Swedish Medical Nanoscience Center, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
    Stereochemical Identification of Glucans by a Donor-Acceptor-Donor Conjugated Pentamer Enables Multi-Carbohydrate Anatomical Mapping in Plant Tissues2019In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 26, no 7, p. 4253-4264Article in journal (Refereed)
    Abstract [en]

    Optotracing is a novel method for analytical imaging of carbohydrates in plant and microbial tissues. This optical method applies structure-responsive oligothiophenes as molecular fluorophores emitting unique optical signatures when bound to polysaccharides. Herein, we apply Carbotrace680, a short length anionic oligothiophene with a central heterocyclic benzodithiazole (BTD) motif, to probe for different glucans. The donor-acceptor-donor type electronic structure of Carbotrace680 provides improved spectral properties compared to oligothiophenes due to the possibility of intramolecular charge-transfer transition to the BTD motif. This enables differentiation of glucans based on the glycosidic linkage stereochemistry. Thus -configured starch is readily differentiated from -configured cellulose. The versatility of optotracing is demonstrated by dynamic monitoring of thermo-induced starch remodelling, shown in parallel by spectrophotometry and microscopy of starch granules. Imaging of Carbotrace680 bound to multiple glucans in plant tissues provided direct identification of their physical locations, revealing the spatial relationship between structural (cellulose) and storage (starch) glucans at sub-cellular scale. Our work forms the basis for the development of superior optotracers for sensitive detection of polysaccharides. Our non-destructive method for anatomical mapping of glucans in biomass will serve as an enabling technology for developments towards efficient use of plant-derived materials and biomass.

  • 322.
    Christoula, Amalia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Towards a sustainable substitute for Acrylonitrile Butadiene Styrene (ABS) in automotive industry2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis aims to develop sustainable replacement for Acrylonitrile Butadiene Styrene (ABS) in high-impact applications within construction equipment’s Cab interior. Adhering to the principles of Green Chemistry and Engineering, the study focused on developing and accessing an environmentally friendly substitute for ABS, a commonly used non-biodegradable plastic. Investigating novel materials with a tailored requirements list is vital in materials science and engineering. Theoretical approaches can yield results which drive further innovation, ensuring comprehensive alignment with application expectations through a holistic approach to address critical factors. Following this guideline, the chosen alternative was Polylactide (PLA), fortified with a blend of lignocellulose nanofibers (LCNFs) and natural rubber (NR) at a 10 wt.% concentration, with the addition of Maleic Anhydride (MA) as a compatibilizer. This modification strategy aimed to enhance PLA's strength and reduce its brittleness. The investigation encompassed various parameters, including different LCNF drying methods and variations in additive treatment before melt-mixing with PLA. The outcomes from thermal analysis indicated that the inclusion of reinforcements does not significantly affect the degradation temperature of the PLA matrix. Crystallinity, on the other hand, was found to be influenced by the presence of lignocellulose reinforcements and natural rubber, with intriguing nuances emerging from the interplay of these components and different treatment methods. PLA-based alternatives performed similarly to low grade ABS and had similar stiffness levels. In terms of elasticity, most materials behaved similarly to neat PLA, but the addition of natural rubber enhanced their deformation capacity. Successful compatibilization between lignocellulose reinforcements, natural rubber, and PLA was assumed from the observed fibrous structures and interwoven networks within the PLA matrix. Additionally, the presence of aggregates and porous structures highlighted the challenges posed by rubber agglomeration. Finally, the observation of larger agglomerates beyond typical interphase sizes raised concerns about brittle behavior, emphasizing the need for optimizing blend toughening strategies. The input for a Life Cycle Assessment (LCA), following a cradle-to-gate approach, is anticipated to show lower carbon emissions for the proposed alternative in comparison to ABS due to the principles of Green Engineering applied in the product design, denoting the environmental viability of the PLA-based substitute.

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  • 323. Chumakov, A.
    et al.
    Brett, Calvin J.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Gordeyeva, Korneliya
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Menzel, D.
    Akinsinde, L. O. O.
    Gensch, M.
    Schwartzkopf, M.
    Cao, W.
    Yin, S.
    Reus, M. A.
    Rübhausen, M. A.
    Müller-Buschbaum, P.
    Söderberg, L. D.
    Roth, S. V.
    Sprayed Nanometer-Thick Hard-Magnetic Coatings with Strong Perpendicular Anisotropy for Data Storage Applications2022In: ACS Applied Nano Materials, E-ISSN 2574-0970, Vol. 5, no 7, p. 8741-8754Article in journal (Refereed)
    Abstract [en]

    The rapid growth of digital information in the world necessitates a big leap in improving the existing technologies for magnetic recording. For the best modern perpendicular recording, the highest coercivity materials with minimal volume are required. We present a study of a facile technology for establishing mono- and multilayer surfaces from various single-domain flat magnetic nanoparticles that exhibit a strong perpendicular-oriented magnetic moment on solid and flexible substrates. Surfactant-free, hard ferromagnetic, and single-domain anisotropic strontium hexaferrite SrFe12O19nanoparticles with a perpendicular magnetic moment orientation and two different aspect ratios are self-ordered into magnetic thin nanofilms, exploiting the templating effect of cellulose nanofibrils and magnetic fields. Uniform magnetic coatings obtained by the scalable layer-by-layer spray deposition from a monolayer coverage up to thicknesses of a few tens of nanometers show a preferred in-plane orientation of the hard-magnetic nanoparticles. High coercivities of the films of up to 5 kOe and a high perpendicular anisotropy of Mr⊥/Ms> 80% are found. The application of the magnetic field during film deposition ensures additional improvement in perpendicular magnetic anisotropy and the appearance of residual magnetization in the film of up to 0.6Ms. For low-aspect-ratio nanoparticles stacked in periodic planar structures, the signs of the photonic band gap are revealed. The ability to create scalable, thin magnetic structures based on nanosized particles/building blocks opens great opportunities for their application in a wide variety of optoelectronic and magnetic storage devices.

  • 324.
    Chumakova, Aleksandra
    et al.
    Outstation at Heinz Maier-Leibnitz Zentrum (MLZ), Institute of Crystallography (IfK), RWTH Aachen University, Lichtenbergstrasse 1, Garching, 85747, Germany; European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble, 38000, France.
    Kirner, Felizitas
    Department of Earth and Environmental Sciences, Section of Crystallography, Ludwig-Maximilians-Universität München (LMU), Theresienstr. 41C, Munich, 80333, Germany.
    Chumakov, Andrei
    Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, Hamburg, 22607, Germany.
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, Hamburg, 22607, Germany.
    Bosak, Alexeï
    European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble, 38000, France.
    Sturm, Elena V.
    Department of Earth and Environmental Sciences, Section of Crystallography, Ludwig-Maximilians-Universität München (LMU), Theresienstr. 41C, Munich, 80333, Germany.
    Exploring the Crystalline Structure of Gold Mesocrystals Using X-ray Diffraction2023In: Crystals, ISSN 2073-4352, Vol. 13, no 8, article id 1204Article in journal (Refereed)
    Abstract [en]

    Mesocrystals are a class of nanostructured material where individual nanocrystals are arranged in a distinct crystallographic orientation. The multiple-length-scale order in such materials plays an essential role in the emergent physical and chemical phenomena. Our work studies the structure of a faceted mesocrystal composed of polystyrene-functionalized single crystalline gold nanoparticles using complementary ultrasmall- and wide-angle X-ray scattering (USAXS and WAXS) with electron microscopy. The results of the data analysis shed some light on the details of the microscopic structure of mesocrystals and their structuration principle.

  • 325.
    Ciftci, Göksu Cinar
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Larsson, Per A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Riazanova, Anastasiia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Øvrebø, H.H.
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Tailoring of rheological properties and structural polydispersity effects in microfibrillated cellulose suspensions2020In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 27, no 16, p. 9227-9241Article in journal (Refereed)
    Abstract [en]

    Abstract: Industrial production of low-charge microfibrillated cellulose (MFC) typically results in wide fibril size distributions. This polydispersity influences viscosity, overall colloidal stability, and rheological properties of MFC suspensions and gels in aqueous systems. In this work, a systematic rheological analysis is performed for industrially prepared MFC and fractions of different size distributions. Gel formation and flow characteristics (e.g., shear-thinning) of each fraction are examined under neutral and acidic conditions and compared with the unfractionated MFC suspension. The effects of size, aspect ratio, and surface charge on the rheology of semi-dilute MFC suspensions are discussed. The results demonstrate that particle size and aspect ratio distribution control the viscoelasticity and shear-thinning properties of MFC suspensions. An increased fraction of small diameter nanofibrils, by ex situ addition of the fine particles with high aspect ratio or removal of the coarsest particles (with lower aspect ratio) by fractionation, significantly enhances the storage modulus and the yield stress of the complex mixture, compared to the properties of the coarser fractions. New insights are also reported on the tailoring of the rheology of highly polydisperse fibrillar mixtures, where the rheological contributions of each fraction are discussed. Graphic abstract: [Figure not available: see fulltext.].

  • 326.
    Ciftci, Göksu Cinar
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Larsson, Per
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Riazanova, Anastasia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Karppinen, Anni
    Borregaard AS, Sarpsborg, Norway..
    Ovrebo, Hans Henrik
    Borregaard AS, Sarpsborg, Norway..
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Influence of microfibrillated cellulose fractions on the rheology of water suspensions: Colloidal interactions and viscoelastic properties2018In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Article in journal (Other academic)
  • 327.
    Cobo Sanchez, Carmen
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Inorganic and organic polymer-grafted nanoparticles: their nanocomposites and characterization2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Nanocomposites (NCs) have been widely studied in the past decades due to the promising properties that nanoparticles (NPs) offer to a polymer matrix, such as increased thermal stability and non-linear electrical resistivity. It has also been shown that the interphase between the two components is the key to achieving the desired improvements. In addition, polymer matrices are often hydrophobic while NPs are generally hydrophilic, leading to NP aggregation. To overcome these challenges, NPs can be surface-modified by adding specific molecules and polymers. In the present work, a range of organic and inorganic NPs have been surface-modified with polymers synthesized by atom transfer radical polymerization (ATRP) or surface-initiated ATRP (SI-ATRP).Cellulose nanofibrils (CNF) and cellulose nanocrystals (CNC) are highly crystalline NPs that can potentially increase the Young’s modulus of the NC. In this study, a matrix-free NC was prepared by physisorption of a block-copolymer containing a positively charged (quaternized poly(2-(dimethylamino)ethyl methacrylate), qPDMAEMA) and a thermo-responsive (poly di(ethylene glycol) methyl ether methacrylate, PDEGMA). The modified CNF exhibited a thermo-responsive, reversible behavior. CNCs were polymer-modified either via SI-ATRP or physisorbed with poly (butyl methacrylate) (PBMA) to improve the dispersion and interphase between them and a polycaprolactone (PCL) matrix during extrusion. The mechanical properties of the NCs containing CNC modified via SI-ATRP were superior to the reference and unmodified materials, even at a high relative humidity.Reduced graphene oxide (rGO) and aluminum oxide (Al2O3) are interesting for electrical and electronic applications. However, the matrices used for these applications, such as poly(ethylene-co-butyl acrylate) (EBA) and low density polyethylene (LDPE) are mainly hydrophobic, while the NPs are hydrophilic. rGO was modified via SI-ATRP using different chain lengths of PBMA and subsequently mixed with an EBA matrix. Al2O3 was modified with two lengths of poly(lauryl methacrylate) (PLMA), and added to LDPE prior to extrusion. Agglomeration and dispersion of the NCs were dependent on the lengths and miscibilities of the grafted polymers and the matrices. rGO-EBA NCs showed non-linear direct current (DC) resistivity upon modification, as the NP dispersion improved with increasing PBMA length. Al2O3-LDPE systems improved the mechanical properties of the NCs when low amounts of NPs (0.5 to 1 wt%) were added, while decreasing power dissipation on the material.Finally, PLMA-grafted NPs with high polymer quantities and two grafting densities in Al2O3 and silicon oxide (SiO2) nanoparticles were synthesized by de-attaching some of the silane groups from the surfaces, either by hydrolysis or by a mild tetrabutylammonium fluoride (TBAF) cleavage. These compounds were characterized and compared to the bulk PLMA, and were found to have very interesting thermal properties.

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    PhD Thesis Carmen Cobo
  • 328.
    Cobo Sanchez, Carmen
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Karlsson, Mattias
    Wåhlander, Martin
    Hillborg, Henrik
    Malmström, Eva
    Nilsson, Fritjof
    Characterization of Reduced and Surface-modified Graphene Oxide in EBA Composites for Electrical ApplicationsManuscript (preprint) (Other academic)
    Download full text (pdf)
    fulltext
  • 329.
    Cobo Sanchez, Carmen
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Malmström, Eva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Matrix-free Nanocomposites based on Poly(lauryl methacrylate)-Grafted Nanoparticles: Effect of Graft Length and Grafting DensityManuscript (preprint) (Other academic)
    Download full text (pdf)
    fulltext
  • 330.
    Colding-Rasmussen, Thomas
    et al.
    Department of Orthopedic Surgery, Hvidovre University Hospital, Kettegaard Allé 30, Hvidovre, 2650, Denmark.
    Schwarzenberg, Peter
    AO Research Institute Davos, Clavadelerstrasse 8, Davos, 7270, Switzerland.
    Horstmann, Peter Frederik
    Department of Orthopedic Surgery, Gentofte Hospital, Gentofte Hospitalsvej 1, Hellerup, 2900, Denmark.
    Ottesen, Casper Bent Smedegaard
    Department of Orthopedic Surgery, Copenhagen University Hospital, Blegdamsvej 9, Copenhagen, Rigshospitalet, 2100, Denmark.
    San Jacinto García, Jorge
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Hutchinson, Daniel John
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Malkoch, Michael
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Petersen, Michael Mørk
    epartment of Orthopedic Surgery, Copenhagen University Hospital, Blegdamsvej 9, Copenhagen, Rigshospitalet, 2100, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, Copenhagen, 2200, Denmark.
    Varga, Peter
    AO Research Institute Davos, Clavadelerstrasse 8, Davos, 7270, Switzerland.
    Tierp-Wong, Christian Nai En
    Department of Orthopedic Surgery, Hvidovre University Hospital, Kettegaard Allé 30, Hvidovre, 2650, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, Copenhagen, 2200, Denmark.
    Biomechanical Variability and Usability of a Novel Customizable Fracture Fixation Technique2023In: Bioengineering, E-ISSN 2306-5354, Vol. 10, no 10, article id 1146Article in journal (Refereed)
    Abstract [en]

    A novel in situ customizable osteosynthesis technique, Bonevolent™ AdhFix, demonstrates promising biomechanical properties under the expertise of a single trained operator. This study assesses inter- and intra-surgeon biomechanical variability and usability of the AdhFix osteosynthesis platform. Six surgeons conducted ten osteosyntheses on a synthetic bone fracture model after reviewing an instruction manual and completing one supervised osteosynthesis. Samples underwent 4-point bending tests at a quasi-static loading rate, and the maximum bending moment (BM), bending stiffness (BS), and AdhFix cross-sectional area (CSA: mm²) were evaluated. All constructs exhibited a consistent appearance and were suitable for biomechanical testing. The mean BM was 2.64 ± 0.57 Nm, and the mean BS was 4.35 ± 0.44 Nm/mm. Statistically significant differences were observed among the six surgeons in BM (p < 0.001) and BS (p = 0.004). Throughout ten trials, only one surgeon demonstrated a significant improvement in BM (p < 0.025), and another showed a significant improvement in BS (p < 0.01). A larger CSA corresponded to a statistically significantly higher value for BM (p < 0.001) but not for BS (p = 0.594). In conclusion, this study found consistent biomechanical stability both across and within the surgeons included, suggesting that the AdhFix osteosynthesis platform can be learned and applied with minimal training and, therefore, might be a clinically viable fracture fixation technique. The variability in BM and BS observed is not expected to have a clinical impact, but future clinical studies are warranted.

  • 331.
    Colson, Jerome
    et al.
    Univ Nat Resources & Life Sci Vienna, Dept Mat Sci & Proc Engn, Inst Wood Technol & Renewable Mat, Konrad Lorenz Str 24, A-3430 Tulin, Austria..
    Pettersson, Torbjörn
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Asaadi, Shirin
    Aalto Univ, Sch Chem Engn, Dept Bioprod & Biosyst, Vuorimiehentie 1, Espoo 02150, Finland..
    Sixta, Herbert
    Aalto Univ, Sch Chem Engn, Dept Bioprod & Biosyst, Vuorimiehentie 1, Espoo 02150, Finland..
    Nypelo, Tiina
    Chalmers Univ Technol, Dept Chem & Chem Technol, Kemigarden 4, S-41296 Gothenburg, Sweden..
    Mautner, Andreas
    Univ Vienna, Fac Chem, Inst Mat Chem & Res, Wahringer Str 42, A-1090 Vienna, Austria..
    Konnerth, Johannes
    Univ Nat Resources & Life Sci Vienna, Dept Mat Sci & Proc Engn, Inst Wood Technol & Renewable Mat, Konrad Lorenz Str 24, A-3430 Tulin, Austria..
    Adhesion properties of regenerated lignocellulosic fibres towards poly (lactic acid) microspheres assessed by colloidal probe technique2018In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 532, p. 819-829Article in journal (Refereed)
    Abstract [en]

    In the field of polymer reinforcement, it is important to understand the interactions involved between the polymer matrix and the reinforcing component. This paper is a contribution to the fundamental understanding of the adhesion mechanisms involved in natural fibre reinforced composites. We report on the use of the colloidal probe technique for the assessment of the adhesion behaviour between poly(lactic acid) microspheres and embedded cross-sections of regenerated lignocellulosic fibres. These fibres consisted of tailored mixtures of cellulose, lignin and xylan, the amount of which was determined beforehand. The influence of the chemical composition of the fibres on the adhesion behaviour was studied in ambient air and in dry atmosphere. In ambient air, capillary forces resulted in larger adhesion between the sphere and the fibres. Changing the ambient medium to a dry nitrogen atmosphere allowed reducing the capillary forces, leading to a drop in the adhesion forces. Differences between fibres of distinct chemical compositions could be measured only on freshly cut surfaces. Moreover, the surface energy of the fibres was assessed by inverse gas chromatography. Compared to fibres containing solely cellulose, the presence of lignin and/or hemicellulose led to higher adhesion and lower surface energy, suggesting that these chemicals could serve as natural coupling agents between hydrophobic and hydrophilic components.

  • 332. Conti, S.
    et al.
    Martínez-Domingo, C.
    Lay, M.
    Terés, L.
    Vilaseca, Fabiola
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Ramon, E.
    Nanopaper-Based Organic Inkjet-Printed Diodes2020In: Advanced Materials Technologies, E-ISSN 2365-709XArticle in journal (Refereed)
    Abstract [en]

    The rise of internet of things (IoTs) applications has led to the development of a new generation of light-weight, flexible, and cost-effective electronics. These devices and sensors have to be simultaneously easily replaceable and disposable while being environmentally sustainable. Thus, the introduction of new functionalized materials with mechanical flexibility that can be processed using large-area and facile fabrication methods (as, for example, printing technologies) has become a matter of great interest in the scientific community. In this context, cellulose nanofibers (CNFs) are renewable, affordable, robust, and nontoxic materials that are rapidly emerging as components for eco-friendly electronics. Their combination with conductive polymers (CPs) to obtain conductive nanopapers (CNPs) allows moving their functionality from just substrates to active components of the device. In this work, a route for the inkjet-printing of organic diodes is outlined. The proposed strategy is based on the use of CNPs as both substrates and bottom electrodes onto which insulator and organic semiconducting layers are deposited to fabricate novel diode structures. Remarkable rectification ratios of up to 1.2 × 103 at |3 V| and a current density up to 5.1 µA cm−2 are achieved. As a proof-of-concept of the potentiality of the approach for versatile, low-temperature, and disposable sensing applications, an NO2 gas sensor is presented. 

  • 333.
    Cortes Ruiz, Maria F.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Tailoring and Characterization of Polymer-linked Fibrillar Structures2024Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The development of sustainable and renewable materials is paramount in today’s society. As the most abundant biopolymer on Earth, cellulose from cellulose-rich fibres is an excellent alternative for advanced and innovative material solutions. Nonetheless, competing with the impressive material properties and the low manufacturing costs of fossil-based plastics imposes great challenges. To increase the potential of cellulose fibres in a broader set of applications, the material properties of cellulose need to be tuned depending on the application. An in-depth study of the fibre structure and the application of different tailoring techniques is required to induce tailoring of the physical and chemical properties of the cellulose fibre materials. 

    This thesis focuses on the structure-property relationship of fibrillar hydrogel networks as model structures for the delignified wet-fibre wall. First, a mathematical framework was developed to describe the characteristics of the swelling and mechanical behaviour of anisotropic fibrillar structures, considering the fibril aspect ratio, surface chemistry of the fibrils, and electrolyte concentration in the system. A chemical functionalisation was then introduced to the fibrillar structure, which provided the CNFs with colloidal stability and the ability to participate in free radical polymerisation with monomers and telechelic oligomers. As a result, fibrillar networks were crosslinked with flexible polymer links that provided the network with different mechanical and chemical properties. Additionally, by tailoring the molecular weight of the crosslinks, the ionic strength of the solution, and even the aspect ratio of the fibrils, the mechanical properties of the network were tuned to be either stiffer or more ductile. 

    Finally, an innovative and more sustainable approach was developed to introduce charge and alkene functionality to the fibres. Following the lessons learned from the CNF model investigations, a polymerisation approach was developed in the presence of functionalised fibres. The polymers were grown from the fibre wall, followed by radical crosslinking to create strong Fibre reinforced hydrogel structures. Depending on the application, the method can be easily applied to introduce other types of molecules and functionalities to the fibres and tailor the properties of the fibres to suit a wide range of applications.

  • 334.
    Cortes Ruiz, Maria F.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Brusentsev, Yury
    Abo Akad Univ, Lab Nat Mat Technol, Turku 20500, Finland..
    Lindstrom, Stefan B.
    Mid Sweden Univ, FSCN Res Ctr, S-85230 Sundsvall, Sweden..
    Xu, Chunlin
    Abo Akad Univ, Lab Nat Mat Technol, Turku 20500, Finland..
    Wagberg, Lars
    Shape-recovering nanocellulose networks: Preparation, characterization and modeling2023In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 315, p. 120950-, article id 120950Article in journal (Refereed)
    Abstract [en]

    Development of strong cellulose nanofibril (CNF) networks for advanced applications, such as in the biomedical field, is of high importance owing to the biocompatible nature and plant-based origin of cellulose nanofibrils. Nevertheless, lack of mechanical strength and complex synthesis methods hinder the application of these ma-terials in areas where both toughness and manufacturing simplicity are required. In this work, we introduce a facile method for the synthesis of a low solid content (< 2 wt%), covalently crosslinked CNF hydrogel where Poly (N-isopropylacrylamide) (NIPAM) chains are utilized as crosslinks between the nanofibrils. The resulting net-works have the capability to fully recover the shape in which they were formed after various drying and rewetting cycles. Characterization of the hydrogel and its constitutive components was performed using X-ray scattering, rheological investigations and uniaxial testing in compression. Influence of covalent crosslinks was compared with networks crosslinked by the addition of CaCl2. Among other things the results show that the mechanical properties of the hydrogels can be tuned by controlling the ionic strength of the surrounding me-dium. Finally, a mathematical model was developed based on the experimental results, which describes and predicts to a decent degree the large-deformation, elastoplastic behavior, and fracture of these networks.

  • 335.
    Cortes Ruiz, Maria F.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Garemark, Jonas
    Wood Materials Science, Institute for Building Materials, ETH Zurich, Zurich, Switzerland.
    Ritter, Maximilian
    Wood Materials Science, Institute for Building Materials, ETH Zurich, Zurich, Switzerland.
    Brusentsev, Yury
    Laboratory of Molecular Science and Engineering, Åbo Akademi, Åbo, Finland.
    Larsson, Per Tomas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Research Institutes of Sweden RISE, Stockholm, Sweden.
    Olsen, Peter
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Structure-properties relationships of defined CNF single-networks crosslinked by telechelic PEGs2024In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 339, article id 122245Article in journal (Refereed)
    Abstract [en]

    The high structural anisotropy and colloidal stability of cellulose nanofibrils' enable the creation of self-standing fibrillar hydrogel networks at very low solid contents. Adding methacrylate moieties on the surface of TEMPO oxidized CNFs allows the formation of more robust covalently crosslinked networks by free radical polymerization of acrylic monomers, exploiting the mechanical properties of these networks more efficiently. This technique yields strong and elastic networks but with an undefined network structure. In this work, we use acrylate-capped telechelic polymers derived from the step-growth polymerization of PEG diacrylate and dithiothreitol to crosslink methacrylated TEMPO-oxidized cellulose nanofibrils (MATO CNF). This combination resulted in flexible and strong hydrogels, as observed through rheological studies, compression and tensile loading. The structure and mechanical properties of these hydrogel networks were found to depend on the dimensions of the CNFs and polymer crosslinkers. The structure of the networks and the role of individual components were evaluated with SAXS (Small-Angle X-ray Scattering) and photo-rheology. A thorough understanding of hybrid CNF/polymer networks and how to best exploit the capacity of these networks enable further advancement of cellulose-based materials for applications in packaging, soft robotics, and biomedical engineering.

  • 336.
    Cortes Ruiz, Maria F.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Garemark, Jonas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Ritter, Maximilian
    Brusentsev, Yury
    Larsson, Per Tomas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Olsén, Peter
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Structure-Properties Relationships of Defined CNF Single-Networks Crosslinked by Telechelic PEGsManuscript (preprint) (Other academic)
  • 337.
    Cortes Ruiz, Maria F.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Martin, Judith
    Marcos Celada, Lukas
    Olsén, Peter
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Dual-functionalized Cellulosic Pulp Fibres for Sustainable Fibre Reinforced Hydrogel CompositesManuscript (preprint) (Other academic)
  • 338.
    Coupette, Fabian
    et al.
    Univ Freiburg, Inst Phys, Hermann Herder Str 3, D-79104 Freiburg, Germany..
    Zhang, Long
    INM Leibniz Inst New Mat, Campus D2 2, D-66123 Saarbrucken, Germany..
    Kuttich, Bjoern
    INM Leibniz Inst New Mat, Campus D2 2, D-66123 Saarbrucken, Germany..
    Chumakov, Andrei
    Deutsch Elektronen Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. Deutsch Elektronen Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.;.
    Gonzalez-Garcia, Lola
    INM Leibniz Inst New Mat, Campus D2 2, D-66123 Saarbrucken, Germany..
    Kraus, Tobias
    INM Leibniz Inst New Mat, Campus D2 2, D-66123 Saarbrucken, Germany.;Saarland Univ, Colloid & Interface Chem, Campus D2 2, D-66123 Saarbrucken, Germany..
    Schilling, Tanja
    Univ Freiburg, Inst Phys, Hermann Herder Str 3, D-79104 Freiburg, Germany..
    Percolation of rigid fractal carbon black aggregates2021In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 155, no 12, article id 124902Article in journal (Refereed)
    Abstract [en]

    We examine network formation and percolation of carbon black by means of Monte Carlo simulations and experiments. In the simulation, we model carbon black by rigid aggregates of impenetrable spheres, which we obtain by diffusion-limited aggregation. To determine the input parameters for the simulation, we experimentally characterize the micro-structure and size distribution of carbon black aggregates. We then simulate suspensions of aggregates and determine the percolation threshold as a function of the aggregate size distribution. We observe a quasi-universal relation between the percolation threshold and a weighted average radius of gyration of the aggregate ensemble. Higher order moments of the size distribution do not have an effect on the percolation threshold. We conclude further that the concentration of large carbon black aggregates has a stronger influence on the percolation threshold than the concentration of small aggregates. In the experiment, we disperse the carbon black in a polymer matrix and measure the conductivity of the composite. We successfully test the hypotheses drawn from simulation by comparing composites prepared with the same type of carbon black before and after ball milling, i.e., on changing only the distribution of aggregate sizes in the composites.& nbsp;

  • 339.
    Cui, Yuxiao
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymeric Materials.
    Han, Tong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Process.
    Svagan, Anna Justina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Achieving carbonized minitablet-shaped structures from lignin: The importance of heating rate on shape2023In: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 176, p. 106260-, article id 106260Article in journal (Refereed)
    Abstract [en]

    Shape-anisotropic building blocks are vital in the creation of hierarchical materials in nature, as it enables directional alignment, property anisotropy and overall functionality improvement in biological materials. Likewise, the performance of carbonized superstructures could potentially be more precisely designed by using anisotropic building blocks. Lignin represents an important and sustainable alternative in the production of carbonized materials, which is due to its abundance and high carbon content (∼60%). However, to expand its utility, for producing carbonized shape-anisotropic materials, adequate synthesis and pyrolysis-protocols are essential. Here, a fractionated and acetylated Kraft lignin was used to successfully self-assemble shape-anisotropic microcapsules. Then a carbonization procedure (slow heating at 0.6 °C min−1), that retained the original shape-anisotropy after carbonization, was developed. The formation mechanism was discussed as a function of the heating rate. The overall strategy was template-free and the attained shape-anisotropies were well-defined and narrow in size distribution. This is a scalable route for achieving shape-anisotropic carbonized building blocks from lignin.

  • 340.
    Cui, Yuxiao
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymeric Materials.
    Lawoko, Martin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Svagan, Anna Justina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    High Value Use of Technical Lignin. Fractionated Lignin Enables Facile Synthesis of Microcapsules with Various Shapes: Hemisphere, Bowl, Mini-tablets, or Spheres with Single Holes2020In: ACS Sustainable Chemistry and Engineering, E-ISSN 2168-0485, Vol. 8, no 35, p. 13282-13291Article in journal (Refereed)
    Abstract [en]

    Anisotropic carbon-rich microcapsule morphologies are of great value in many applications including catalysis, energy storage, biomedicine, and osmosis-triggered drug delivery, due to an observed shape effect. However, high-precision synthesis, to generate large yields of well-defined anisotropic shapes, is generally challenging. Here, we show for the first time that a modified carbon-rich waste-material, a fractionated and acetylated Kraft lignin, enables facile production of large amounts of well-defined "acorn-like" microcapsules with heterogeneous shell thicknesses. This is due to the inherent physicochemical properties of the fractionated lignin at the oil/water (O/W) interface. The acorn-shape is strongly related to two distinct lignin-molecule populations, that phase separate during microcapsule formation. Fine-tuning the post-treatment conditions (pressure or hydrothermal temperature) results in a number of different microcapsule shapes; hemisphere, bowl, mini-tablets, or spheres with single holes. Further chemical modification to their surfaces is also demonstrated. The present study provides a new library of shape-anisotropic carbon-rich building blocks that open new avenues for assembling hierarchical material with a high level of complexity.

  • 341.
    Cui, Yuxiao
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymeric Materials.
    Sheng, Xia
    Henan Agricultural University, Coll Sci, Zhengzhou, 450000, China.
    Anusuyadevi, Prasaanth Ravi
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Lawoko, Martin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Svagan, Anna Justina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Self-assembled carbon spheres prepared from abundant lignin and urea for photocatalytic and self-propelling applications2021In: Carbon Trends, ISSN 2667-0569, Vol. 3, p. 100040-, article id 100040Article in journal (Refereed)
    Abstract [en]

    Lignin is a valuable bio-resource in the manufacturing of carbon-based functional materials, because of its large carbon content (~60%), various phenolic structural units, abundancy and sustainability. Here, we explored its use in photocatalytic and self-propelling applications. First, hydroxyl-abundant lignin-based carbon precursor particles, HCLSs, were produced by hydrothermal carbonization of lignin-based microcapsules (LCs). Then, by heating urea coated HCLSs, carbon spheres with a layer of graphitic carbon nitride (g-C3N4) were produced. The presence of surface available -OH groups on the HCLSs, were critical in the formation mechanism. Under visible-light irradiation, the photocatalytic spheres exhibited enhanced activity (49% of the model pollutant remained after 60 min, at 100 mW cm−2) and possessed a three times higher average removal rate constant compared to that of g-C3N4 powder. The g-C3N4 powder was obtained when heating urea only. Additionally, by introducing a Pt/Pd coating on only one side of the composite spheres, the spheres were made self-propelling in the presence of a fuel (H2O2). This work provides new insights into the preparation principles of lignin-based photocatalytic spheres for effective solar photocatalysis applications.

  • 342.
    Cui, Yuxiao
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymeric Materials.
    Subramaniyam, Chandrasekar M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Li, Lengwan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Han, Tong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Kang, Mina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Li, Jian
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Zhao, Luyao
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Wei, Xin-Feng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Svagan, Anna Justina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Hamedi, Mahiar
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Hierarchical soot nanoparticle self-assemblies for enhanced performance as sodium-ion battery anodes2022In: Journal of Materials Chemistry A, ISSN 2050-7488, E-ISSN 2050-7496, Vol. 10, no 16, p. 9059-9066Article in journal (Refereed)
    Abstract [en]

    The drawbacks of amorphous hard carbon are its low conductivity and structural instability, due to its large volume change and the occurrence of side reactions with the electrolyte during cycling. Here, we propose a simple and rapid method to address these disadvantages; we used an emulsion solvent-evaporation method to create hierarchically structured microparticles of hard carbon nanoparticles, derived from soot, and multi-walled-carbon-nanotubes at a very low threshold of 2.8 wt%. These shrub-ball like microparticles have well-defined void spaces between different nanostructures of carbon, leading to an increased surface area, lower charge-resistance and side reactions, and higher electronic conductivity for Na+ insertion and de-insertion. They can be slurry cast to assemble Na+ anodes, exhibiting an initial discharge capacity of 713.3 mA h g(-1) and showing long-term stability with 120.8 mA h g(-1) at 500 mA g(-1) after 500 cycles, thus outperforming neat hard carbon nanoparticles by an order of magnitude. Our work shows that hierarchical self-assembly is attractive for increasing the performance of microparticles used for battery production.

  • 343. Cunha, Ana G.
    et al.
    Lundahl, Meri
    Ansari, Farhan
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Johansson, Leena-Sisko
    Campbell, Joseph M.
    Rojas, Orlando J.
    Surface Structuring and Water Interactions of Nanocellulose Filaments Modified with Organosilanes toward Wearable Materials2018In: ACS APPLIED NANO MATERIALS, ISSN 2574-0970, Vol. 1, no 9, p. 5279-5288Article in journal (Refereed)
    Abstract [en]

    Colloidal dispersions of cellulose nanofibrils (CNFs) are viable ternatives to cellulose II dissolutions used for filament spinning. e porosity and water vapor affinity of CNF filaments make them itable for controlled breathability. However, many textile plications also require water repellence. Here, we investigated the fects of postmodification of wet-spun CNF filaments via chemical vapor position (CVD). Two organosilanes with different numbers of methyl bstituents were considered. Various surface structures were achieved, ther as continuous, homogeneous coating layers or as ree-dimensional, hairy-like assemblies. Such surface features reduced e surface energy, which significantly affected the interactions with ter. Filaments with water contact angles of up to 116 were obtained, d surface energy measurements indicated the possibility of developing phiphobicity. Dynamic vapor sorption and full immersion experiments re carried out to inquire about the interactions with water, whether the liquid or gas forms. Mechanical tests revealed that the wet rength of the modified filaments were almost 3 times higher than that the unmodified precursors. The hydrolytic and mechanical stabilities the adsorbed layers were also revealed. Overall, our results shed ght on the transformation of aqueous dispersions of CNFs into laments that are suited for controlled interactions with water via ncurrent hydrolysis and condensation reactions in CVD, while intaining the moisture buffering capacity and breathability of related ructures.

  • 344.
    Curman, Johan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Wood Chemistry and Pulp Technology.
    Dissolution of cellulose in cold alkali followed by precipitation2024Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Cellulose is the most abundant biopolymer on earth and is an important material in developing a sustainable society. The properties of cellulose can be modified by chemical treatment or reactions. The reactivity is fairly low in crystalline cellulose but can be increased if the dense crystal structure is disrupted by e.g. swelling or dissolution followed by precipitation. Dissolution of cellulose is difficult and this project aims to dissolve cellulose from three sources (Avicel and two sulfate pulps). One of the pulps had a tiny fraction of softwood and mostly birch and aspen, hardwood pulp (HW). The other of the pulps was made of pine and spruce, softwood pulp (SW). The raw materials were dissolved in sodium hydroxide (NaOH) and then precipitated with two acids and an anti-solvent (acetic acid (HOAc), sulfuric acid (H2SO4), or ethanol (EtOH)). The yields of the precipitated products were compared.

    Avicel 2.5 wt% was dissolved in NaOH solution (10%) at 5 oC and precipitated with the two acids and EtOH to determine the highest yield. HOAc gave the best results and was used in the following experiments on pulp. The solubility of pulps was low and the undissolved pulp had to be separated by centrifugation before precipitation of the solution. Hydrolyzation of the pulps was performed to increase the solubility and the precipitation yield.

    Dissolution of Avicel in cold NaOH and precipitation was successful. The yield at precipitation with acids was high. There was no peak of maximal yield when the acids were used to precipitate, but EtOH had a maximal yield but lower than for the acids. The results with pulp were not as good as for Avicel. The separated undissolved parts were big for both pulps, but HW was the worst. The yield of precipitation was low as there was less cellulose dissolved that could be precipitated. The hydrolysis of HW and SW was successful. This made it possible to dissolve and precipitate more cellulose from the pulp.

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  • 345. Custodio, C. L.
    et al.
    Yang, Xuan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Wilsby, Astrid
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Waller, Viktor
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Aquino, R. R.
    Tayo, L. L.
    Senoro, D. B.
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Effect of a chemical treatment series on the structure and mechanical properties of abaca fiber (Musa textilis)2020In: Materials Science Forum, Trans Tech Publications, Ltd. , 2020, Vol. 1015, p. 64-69Conference paper (Refereed)
    Abstract [en]

    This study investigates the relationships between the composition, cell wall microstructure, and mechanical properties of the abaca fiber. Raw abaca fibers have undergone a series of sequential chemical treatments (acetone/methanol, boiling water, EDTA, HCl, NaClO2, and NaOH) to selectively remove certain non-cellulosic components (NCCs) in the fiber, such as waxes, water-soluble fragments, pectin, and lignin in a step-by-step manner. Changes in composition, morphology, and mechanical properties were observed using FTIR spectroscopy and ion chromatography, digital microscope and SEM, and tensile tests, respectively. The raw fiber was composed of 23% NCCs, 18% hemicellulose, and 58% cellulose, and exhibited a 17.4 GPa Young’s modulus and a 444 MPa tensile strength. Furthermore, the raw abaca fibers demonstrated a linear tensile graph without yielding, and a planar fracture surface without fiber pull-outs, thus suggesting a highly elastic but brittle nature. At the end of the alkali treatment, the fibrillated fiber was 83% cellulose, yet the stiffness and strength dropped to 7.3 GPa and 55 MPa, respectively, as more components were removed, and microfibril relaxation and realignment have occurred. Load-bearing cellulose and hemicellulose accounted for 42% and 36% of the stiffness, respectively, due to –OH groups capable of hydrogen bonding. 63% of the strength was due to thenative NCC matrices, which contribute a significant role within the cell wall’s load-transfer activities.

  • 346.
    da Costa, Marcus Vinicius Tavares
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. Uppsala University, Division of Applied Mechanics, Department of Materials Science and Engineering.
    Gamstedt, E. Kristofer
    Prediction of loss of barrier properties in cracked thin coatings on polymer substrates subjected to tensile strain2021In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 426, article id 127746Article in journal (Refereed)
    Abstract [en]

    Thin brittle coatings on polymer films are a potentially useful material combination for food packaging applications. The brittle coatings inevitably risk cracking when the package is converted. This strain-induced cracking leads to a loss of the key barrier properties. In design of packaging materials, it would be useful to predict the loss of the oxygen transmission rate (OTR) as a function of the applied tensile strain, which are linked by the crack opening and crack spacing in the coating. Previous works have presented a model that predicts the effect of strain on the OTR in the presence of cracks in the coating. This work uses an improved numerical model based on finite element method (FEM) to predict the oxygen permeability more accurately, especially for thin coatings with high crack densities. The numerical predictions show reasonable correspondence with experimental results for SiOx coatings. These results as well as predictions for previously tested metal-oxide coated polymer films show a significant increase in OTR at crack onset, which suggests that efforts should be made to make the coatings more ductile with higher crack onset strains if the barrier performance should be maintained in converted packages. The quantitative link from deformation over the damage state to barrier properties indicate that mechanics could provide a tool to aid the design of improved food packages with retained barrier capacity.

  • 347. Daenicke, J.
    et al.
    Schubert, D. W.
    Hedenqvist, Mikael S.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Linde, Erik
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Sigl, T.
    Horch, R. E.
    Evaluation of the influence of crosslink density and penetrant size on the diffusion properties of silicone oils into silicone elastomers2019In: Proceedings of the Europe/Africa Conference Dresden 2017 – Polymer Processing Society PPS, American Institute of Physics (AIP), 2019, Vol. 2055Conference paper (Refereed)
    Abstract [en]

    Driven by the continuing discussion on safety and quality of silicone breast implants, they have turned into focus of this study with respect to the diffusivity of low molar mass components from the silicone gel filling into the silicone breast implant shell. Therefore, the diffusivity of silicone oils into silicone elastomers were analysed by means of the crosslink density and the penetrant size. The study was focused on the diffusion of the cyclic siloxanes Octamethylcyclotetrasiloxane (D4), Decamethylcyclopentasiloxane (D5) and Dodecamethyl-cyclohexasiloxane (D6) due to their potential occurrence in silicone breast implants. The analysis of the diffusion behavior was carried out with silicone breast implant shells taken from explants and tailor-made silicone elastomer samples varying in crosslink density. Therefore, sorption experiments were performed. The subsequent evaluation of the sorption data yield to the corresponding diffusion properties. Based on the diffusion coefficient related to the crosslink density a model was developed to describe the material behavior.

  • 348.
    Dahlström, C.
    et al.
    Mid Sweden Univ, Dept Chem Engn, Fibre Sci & Commun Network, Holmgatan 10, SE-85170 Sundsvall, Sweden..
    López Durán, Verónica
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Keene, S. T.
    Stanford Univ, Dept Mat Sci & Engn, Geballe Lab Adv Mat, Stanford, CA 94305 USA..
    Salleo, A.
    Stanford Univ, Dept Mat Sci & Engn, Geballe Lab Adv Mat, Stanford, CA 94305 USA..
    Norgren, M.
    Mid Sweden Univ, Dept Chem Engn, Fibre Sci & Commun Network, Holmgatan 10, SE-85170 Sundsvall, Sweden..
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Ion conductivity through TEMPO-mediated oxidated and periodate oxidated cellulose membranes2020In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 233, article id 115829Article in journal (Refereed)
    Abstract [en]

    Cellulose in different forms is increasingly used due to sustainability aspects. Even though cellulose itself is an isolating material, it might affect ion transport in electronic applications. This effect is important to understand for instance in the design of cellulose-based supercapacitors. To test the ion conductivity through membranes made from cellulose nanofibril (CNF) materials, different electrolytes chosen with respect to the Hofmeister series were studied. The CNF samples were oxidised to three different surface charge levels via 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), and a second batch was further cross-linked by periodate oxidation to increase wet strength and stability. The outcome showed that the CNF pre-treatment and choice of electrolyte are both crucial to the ion conductivity through the membranes. Significant specific ion effects were observed for the TEMPO-oxidised CNF. Periodate oxidated CNF showed low ion conductivity for all electrolytes tested due to an inhibited swelling caused by the crosslinking reaction.

  • 349. Darabi, Sozan
    et al.
    Hummel, Michael
    Rantasalo, Sami
    Rissanen, Marja
    Öberg Månsson, Ingrid
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Hilke, Haike
    Byungil, Hwang
    Skrifvars, Mikael
    Hamedi, Mahiar
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Sixta, Herbert
    Lund, Anja
    Müller, Christian
    Green Conducting Cellulose Yarns for Machine Sewn Electronic TextilesManuscript (preprint) (Other academic)
  • 350.
    Darabi, Sozan
    et al.
    Chalmers Univ Technol, Dept Chem & Chem Engn, S-41296 Gothenburg, Sweden.;Chalmers Univ Technol, Wallenberg Wood Sci Ctr, S-41296 Gothenburg, Sweden..
    Hummel, Michael
    Aalto Univ, Dept Bioprod & Biosyst, Espoo 02150, Finland..
    Rantasalo, Sami
    Aalto Univ, Dept Bioprod & Biosyst, Espoo 02150, Finland..
    Rissanen, Marja
    Aalto Univ, Dept Bioprod & Biosyst, Espoo 02150, Finland..
    Öberg Månsson, Ingrid
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Hilke, Haike
    Univ Borås, Fac Text Engn & Business, S-50190 Borås, Sweden..
    Hwang, Byungil
    Chung Ang Univ, Sch Integrat Engn, Seoul 06974, South Korea..
    Skrifvars, Mikael
    Univ Borås, Fac Text Engn & Business, S-50190 Borås, Sweden..
    Hamedi, Mahiar
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Sixta, Herbert
    Aalto Univ, Dept Bioprod & Biosyst, Espoo 02150, Finland..
    Lund, Anja
    Chalmers Univ Technol, Dept Chem & Chem Engn, S-41296 Gothenburg, Sweden..
    Muller, Christian
    Chalmers Univ Technol, Dept Chem & Chem Engn, S-41296 Gothenburg, Sweden.;Chalmers Univ Technol, Wallenberg Wood Sci Ctr, S-41296 Gothenburg, Sweden..
    Green Conducting Cellulose Yarns for Machine-Sewn Electronic Textiles2020In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 12, no 50, p. 56403-56412Article in journal (Refereed)
    Abstract [en]

    The emergence of "green" electronics is a response to the pressing global situation where conventional electronics contribute to resource depletion and a global build-up of waste. For wearable applications, green electronic textile (e-textile) materials present an opportunity to unobtrusively incorporate sensing, energy harvesting, and other functionality into the clothes we wear. Here, we demonstrate electrically conducting wood-based yarns produced by a roll-to-roll coating process with an ink based on the biocompatible polymer:polyelectrolyte complex poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS). The developed e-textile yarns display a, for cellulose yarns, record-high bulk conductivity of 36 Scm(-)(1), which could be further increased to 181 Scm(-)(1) by adding silver nanowires. The PEDOT:PSS-coated yarn could be machine washed at least five times without loss in conductivity. We demonstrate the electrochemical functionality of the yarn through incorporation into organic electrochemical transistors (OECTs). Moreover, by using a household sewing machine, we have manufactured an out-of-plane thermoelectric textile device, which can produce 0.2 mu W at a temperature gradient of 37 K.

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