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  • 1.
    Adolfsson, Karin H.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hassanzadeh, Salman
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Valorization of cellulose and waste paper to graphene oxide quantum dots2015In: RSC Advances, E-ISSN 2046-2069, Vol. 5, no 34, p. 26550-26558Article in journal (Refereed)
    Abstract [en]

    Biobased graphene oxide quantum dots (GOQD) were derived from cellulose via carbon nanospheres (CN) as intermediate products. Solid CN were synthesized from cellulose through microwave-assisted hydrothermal degradation of alpha-cellulose with H2SO4 as a catalyst at 160 degrees C. The obtained CN were further utilized for the synthesis of GOQD by a two-step reaction including 30 minutes of sonication followed by heating at 90 degrees C under O-rich acidic conditions (HNO3). This process broke down the 3D CN to 2D GOQD. The size of the synthesized GOQD was controlled by the heating time, reaching a dot diameter of 3.3 nm and 1.2 nm after 30 and 60 minutes of heating, respectively. The synthesis process and products were characterized by multiple analytical techniques including FTIR, TGA, SEM, TEM, XPS, XRD, BET, DLS and AFM. Interesting optical properties in aqueous solutions were demonstrated by UV/Vis and fluorescence spectroscopy. Finally we demonstrated that corresponding GOQD can be synthesized from waste paper. This production route thus uses renewable and cheap starting materials and relatively mild synthesis procedures leads to instant nanometric production of 2D dots. In addition it enables recycling of low quality waste to value-added products.

  • 2.
    Akan, Rabia
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Parfeniukas, Karolis
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Vogt, Carmen
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Toprak, M. S.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Vogt, Ulrich
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Reaction control of metal-assisted chemical etching for silicon-based zone plate nanostructures2018In: RSC Advances, E-ISSN 2046-2069, Vol. 8, no 23, p. 12628-12634Article in journal (Refereed)
    Abstract [en]

    Metal-assisted chemical etching (MACE) reaction parameters were investigated for the fabrication of specially designed silicon-based X-ray zone plate nanostructures using a gold catalyst pattern and etching solutions composed of HF and H2O2. Etching depth, zone verticality and zone roughness were studied as a function of etching solution composition, temperature and processing time. Homogeneous, vertical etching with increasing depth is observed at increasing H2O2 concentrations and elevated processing temperatures, implying a balance in the hole injection and silica dissolution kinetics at the gold-silicon interface. The etching depth decreases and zone roughness increases at the highest investigated H2O2 concentration and temperature. Possible reasons for these observations are discussed based on reaction chemistry and zone plate design. Optimum MACE conditions are found at HFH2O2 concentrations of 4.7 M:0.68 M and room temperature with an etching rate of ≈0.7 μm min-1, which is about an order of magnitude higher than previous reports. Moreover, our results show that a grid catalyst design is important for successful fabrication of vertical high aspect ratio silicon nanostructures. 

  • 3.
    Alvarez-Asencio, Ruben
    et al.
    RISE Res Inst Sweden, Div Biosci & Mat, SE-11486 Stockholm, Sweden..
    Corkery, Robert
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Ahniyaz, Anwar
    RISE Res Inst Sweden, Div Biosci & Mat, SE-11486 Stockholm, Sweden..
    Solventless synthesis of cerium oxide nanoparticles and their application in UV protective clear coatings2020In: RSC Advances, E-ISSN 2046-2069, Vol. 10, no 25, p. 14818-14825Article in journal (Refereed)
    Abstract [en]

    Colloidal dispersions of cerium oxide nanoparticles are of importance for numerous applications including as catalysts, chemical mechanical polishing agents and additives for UV protective and anticorrosion coatings. Here, concentrated oleate-coated cerium oxide nanoparticles (CeO2 NPs) with a uniform size have been produced by solventless thermolysis of cerium-oleate powder under low pressure at 320 degrees C and subsequently dispersed in hexane. Unlike any previously reported colloidal synthesis process for ceria nanoparticles, this process does not involve any toxic high boiling point organic solvent that requires subsequent removal at high cost. Although the process is very simple, highly concentrated cerium oxide nanoparticles with more than 17 wt% solid content and 70% of the theoretical yield can be easily obtained. Moreover, the size, shape and crystallinity of cerium oxide nanoparticles can be tailored by changing the thermal decomposition temperature and reaction time. Moreover, the new synthesis route developed in this study allows the synthesis of clean and dispersible ceria nanoparticles at a relatively low cost in a single step. The prepared ceria nanoparticles have an excellent UV absorption property and remain transparent to visible light, thus having the potential to replace potentially hazardous organic compounds in UV absorbing clear coatings. As a proof of concept, the prepared dispersions of cerium oxide nanoparticles in hexane were formulated into a solvent borne binder base to develop clear UV protecting coatings for light sensitive substrates. The general synthesis strategy presented in this study is generally applicable for the low-cost production of a concentrated dispersion of metal oxide nanoparticles with minimal environmental impact.

  • 4.
    Andersson, Richard
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Cabedo, L.
    Hedenqvist, Mikael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Olsson, Richard
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Ström, Valter
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Superparamagnetic [sic] nanofibers by electrospinning2016In: RSC Advances, E-ISSN 2046-2069, Vol. 6, no 26, p. 21413-21422Article in journal (Refereed)
    Abstract [en]

    The preparation of superparamagnetic thin fibers by electrospinning dispersions of nanosized magnetite (Fe3O4, SPIO/USPIO) in a PMMA/PEO polymer solution is reported. The saturation magnetization and coercivity were not affected by the concentration (0, 1, 10, 20 wt%) or fiber orientation, showing hysteresis loops with high magnetization (64 A m(2) kg(-1) @ 500 kA m(-1)) and record low coercivity (20 A m(-1)). AC susceptibility measurements vs. temperature at frequencies from 60 to 2 kHz confirmed superparamagnetism. The mechanical properties were only slightly dependent on the particle concentration because the nanoparticles were separately encapsulated by the polymer. A uniform fibre fracture cross section was found at all the investigated particle contents, which suggests a strong interaction at the polymer/particle interface. A theoretical value of the magnetic low field susceptibility was calculated from the Langevin function and compared with measured values. The results show a distinct but concentration-independent anisotropy, favoring magnetization along the fiber orientation with no sign of exchange interaction, explained by complete nanoparticle separation. Superparamagnetism cannot be inferred from particle size alone, so a relevant interpretation and criterion for superparamagnetism is presented, in accordance with Neel's original definition. From the measurements, it can be concluded that magnetic characterization can be used to elucidate the material morphology beyond the resolution of available microscopy techniques (TEM and SEM).

  • 5. Banerjee, Chandrima
    et al.
    Pal, Semanti
    Ahlberg, Martina
    Nguyen, T. N. Anh
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics. Vietnam Acad Sci & Technol, Vietnam.
    Åkerman, Johan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics. Univ Gothenburg, Sweden.
    Barman, Anjan
    All-optical study of tunable ultrafast spin dynamics in [Co/Pd]/NiFe systems: the role of spin-twist structure on Gilbert damping2016In: RSC Advances, E-ISSN 2046-2069, Vol. 6, no 83, p. 80168-80173Article in journal (Refereed)
    Abstract [en]

    We investigate optically induced ultrafast magnetization dynamics in [Co(0.5 nm)/Pd(1 nm)](5)/NiFe(t) exchange-spring samples with tilted perpendicular magnetic anisotropy using a time-resolved magneto-optical Kerr effect magnetometer. The competition between the out-of-plane anisotropy of the hard layer, the in-plane anisotropy of the soft layer and the applied bias field reorganizes the spins in the soft layer, which are modified further with the variation in t. The spin-wave spectrum, the ultrafast demagnetization time, and the extracted damping coefficients - all depend on the spin distribution in the soft layer, while the latter two also depend on the spin-orbit coupling between the Co and Pd layers. The spin-wave spectra change from multimode to single-mode as t decreases. At the maximum field reached in this study, H = 2.5 kOe, the damping shows a nonmonotonic dependence on t with a minimum at t = 7.5 nm. For t < 7.5 nm, intrinsic effects dominate, whereas for t > 7.5 nm, extrinsic effects govern the damping mechanisms.

  • 6.
    Banerjee, Indradumna
    et al.
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    Salih, Tagrid
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    Ramachandraiah, Harisha
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Erlandsson, Johan
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Pettersson, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Araújo, A. C.
    Karlsson, M.
    Russom, Aman
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Slipdisc: A versatile sample preparation platform for point of care diagnostics2017In: RSC Advances, E-ISSN 2046-2069, Vol. 7, no 56, p. 35048-35054Article in journal (Refereed)
    Abstract [en]

    We report a microfluidic sample preparation platform called "Slipdisc" based on slipchip technology. Slipdisc is a rotational slipchip that uses a unique hand-wound clockwork mechanism for precise movement of specially fabricated polycarbonate discs. In operation, the microchannels and microchambers carved on the closely aligned microfluidic discs convert from continuous filled paths to defined compartments using the slip movement. The clockwork mechanism introduced here is characterised by a food dye experiment and a conventional HRP TMB reaction before measuring lactate dehydrogenase (LDH) enzyme levels, which is a crucial biomarker for neonatal diagnostics. The colorimetry based detection of LDH was performed with an unmodified camera and an image analysis procedure based on normalising images and observing changes in red channel intensity. The analysis showed a close to unity coefficient of determination (R2 = 0.96) in detecting the LDH concentration when compared with a standard Chemical Analyser, demonstrating the excellent performance of the slipdisc platform with colorimetric detection. The versatile point of care sample preparation platform should ideally be suited for a multitude of applications at resource-limited settings.

  • 7.
    Biundo, Antonino
    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), Protein Science. KTH, Centres, Science for Life Laboratory, SciLifeLab. ACIB, Konrad Lorenz Str 20, A-3430 Tulln An Der Donau, Austria.
    Subagia, Raditya
    Univ Nat Resources & Life Sci BOKU, Inst Environm Biotechnol, Konrad Lorenz Str 20, A-3430 Tulln An Der Donau, Austria..
    Maurer, Michael
    Univ Appl Sci, Dept Bioengn, Mauerbachstr 43, A-1140 Vienna, Austria..
    Ribitsch, Doris
    ACIB, Konrad Lorenz Str 20, A-3430 Tulln An Der Donau, Austria.;Univ Nat Resources & Life Sci BOKU, Inst Environm Biotechnol, Konrad Lorenz Str 20, A-3430 Tulln An Der Donau, Austria..
    Syrén, Per-Olof
    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), Protein Science. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Guebitz, Georg M.
    ACIB, Konrad Lorenz Str 20, A-3430 Tulln An Der Donau, Austria.;Univ Nat Resources & Life Sci BOKU, Inst Environm Biotechnol, Konrad Lorenz Str 20, A-3430 Tulln An Der Donau, Austria..
    Switched reaction specificity in polyesterases towards amide bond hydrolysis by enzyme engineering2019In: RSC Advances, E-ISSN 2046-2069, Vol. 9, no 62, p. 36217-36226Article in journal (Refereed)
    Abstract [en]

    The recalcitrance of plastics like nylon and other polyamides contributes to environmental problems (e.g. microplastics in oceans) and restricts possibilities for recycling. The fact that hitherto discovered amidases (EC 3.5.1. and 3.5.2.) only show no, or low, activity on polyamides currently obstructs biotechnological-assisted depolymerization of man-made materials. In this work, we capitalized on enzyme engineering to enhance the promiscuous amidase activity of polyesterases. Through enzyme design we created a reallocated water network adapted for hydrogen bond formation to synthetic amide backbones for enhanced transition state stabilization in the polyester-hydrolyzing biocatalysts Humicola insolens cutinase and Thermobifida cellulosilytica cutinase 1. This novel concept enabled increased catalytic efficiency towards amide-containing soluble substrates. The afforded enhanced hydrolysis of the amide bond-containing insoluble substrate 3PA 6,6 by designed variants was aligned with improved transition state stabilization identified by molecular dynamics (MD) simulations. Furthermore, the presence of a favorable water-molecule network that interacted with synthetic amides in the variants resulted in a reduced activity on polyethylene terephthalate (PET). Our data demonstrate the potential of using enzyme engineering to improve the amidase activity for polyesterases to act on synthetic amide-containing polymers.

  • 8.
    Bondarchuk, Sergey V.
    et al.
    Bogdan Khmelnitsky Cherkasy National University, Ukraine.
    Minaev, Boris F.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Bogdan Khmelnitsky Cherkasy National University, Ukraine.
    Thermally accessible triplet state of pi-nucleophiles does exist. Evidence from first principles study of ethylene interaction with copper species2015In: RSC Advances, E-ISSN 2046-2069, Vol. 5, no 15, p. 11558-11569Article in journal (Refereed)
    Abstract [en]

    Three different models of ethylene interaction with copper species, namely, the Cu(100) surface, odd-numbered copper clusters C2H4/Cu-n (where n = 3, 7, 11, 15, 17, 19, 21, 25 and 27) and atomic copper C2H4/Cu were studied theoretically. It was found that the ethylene molecule possesses three different types of bonding depending on the presence of the unpaired spin on the reacting copper atom. These bonding structures demonstrate different types of band gap (bulk) or SOMO-LUMO gaps (cluster/atom), where SOMO stands for the singly occupied and LUMO means the lowest unoccupied molecular orbitals of the copper species. The obtained results are in good agreement with the previous experimental and computational results on the structural, spectral and energetic properties of the studied species. The bulk copper and sub-nanosized clusters (n > 7) build up the mono-pi-bonded ground state complexes with ethylene where the latter species possesses the C-2v symmetry. The single-atom complex C2H4/Cu forms the CS-symmetrical ground state (X) over tilde (2)A' and the excited B-2(2) and B-4 state complexes of the C-2v and C-2 symmetry, respectively. The (X) over tilde (2)A' state complex is mono-sigma-bonded and involves the singlet ethylene moiety. The more tightly bound excited B-2(2) complex has the di-sigma-bonded structure and corresponds to the triplet ethylene. The adiabatic energy difference between the B-2(2) and (X) over tilde (2)A' states is equal to 10.8 kcal mol(-1) and can be ascribed to the singlet-triplet splitting of the ethylene moiety interacting with copper. The QTAIM analysis supports the coordination type of the Cu-C bonds in all the studied complexes. Formation of the C2H4/Cu(100), C2H4/Cu-n and C2H4/Cu species is in accord with the well-known Dewar-Chatt-Duncanson model, in such a way that the opposing sigma-donation step yields the ground state complex ((X) over tilde (2)A'), while the subsequent more expensive supporting pi*-back donation step provides the excited B-2(2) state complex. In the present paper we have developed a computational procedure to optimize the latter complex.

  • 9.
    Bruce, Carl
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Javakhishvili, Irakli
    Fogelström, Linda
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Carlmark, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Hvilsted, Søren
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Well-defined ABA- and BAB-type block copolymers of PDMAEMA and PCL2014In: RSC Advances, E-ISSN 2046-2069, Vol. 4, no 49, p. 25809-25818Article in journal (Refereed)
    Abstract [en]

    Triblock copolymers of ABA- and BAB-type consisting of poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA, A) and poly(epsilon-caprolactone) (PCL, B) have successfully been prepared. PDMAEMA-b-PCL-b-PDMAEMA (ABA) and PCL-b-PDMAEMA-b-PCL (BAB) were synthesised by a combination of ring-opening polymerisation of epsilon-CL, atom transfer radical polymerisation of DMAEMA and end-group conversion, performed through either acylation or azide-alkyne "click" chemistry. All samples were analysed by size exclusion chromatography where it was found that the evaluation of PDMAEMA-containing polymers was difficult due to the thermoresponsivity of PDMAEMA, affecting the solubility of the polymer in the temperature range at which the SEC was operated. From differential scanning calorimetry measurements it was shown that the crystallinity could be altered by changing the order of the blocks; with PDMAEMA as the outer block (ABA), the inherent crystallinity of PCL was destroyed while with PCL as the outer block (BAB), the degree of crystallinity was in the same proximity as for a PCL homopolymer.

  • 10.
    Bu, Junfu
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Jönsson, Pär Göran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Zhao, Zhe
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    The effect of NiO on the conductivity of BaZr0.5Ce0.3Y0.2O3-delta based electrolytes2016In: RSC Advances, E-ISSN 2046-2069, Vol. 6, no 67, p. 62368-62377Article in journal (Refereed)
    Abstract [en]

    The effects of NiO on the sintering behaviors, morphologies and conductivities of BaZr0.5Ce0.3Y0.2O3-delta (BZCY532) based electrolytes were systematically investigated. 1 wt% NiO powder was added by different methods during the sample preparation: (i) added during ball-milling before a powder mixture calcination (named BZCY(Ni) 532), (ii) no NiO addition in the whole preparation procedure (named BZCY532) and (iii) added after a powder mixture calcination (named BZCY532(Ni)). The conductivities of these three kinds of dense BZCY532 ceramics were investigated in dry air, wet N-2 and wet H-2 atmospheres, respectively. Moreover, the electronic contributions to the total conductivities were also identified in a broad oxygen partial pressure range. According to the achieved results, it can be concluded that the dense BZCY(Ni) 532 ceramics showed the best enhanced oxygen and proton conductivities, followed by the BZCY532(Ni) and BZCY532 ceramics. Furthermore, the BZCY(Ni) 532 and BZCY532 ceramics showed a tiny electronic conductivity, when the testing temperatures were lower than 800 degrees C. However, the BZCY532(Ni) ceramics revealed an obvious electronic conduction when they were tested at temperatures of 600-800 degrees C. Therefore, it is preferable to add the NiO during powder preparation, which can lower the sintering temperature and also increase the conductivity of BZCY532-based electrolytes.

  • 11.
    Carrick, Christopher
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Larsson, Per A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Brismar, Hjalmar
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Aidun, Cyrus
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Native and functionalized micrometre-sized cellulose capsules prepared by microfluidic flow focusing2014In: RSC Advances, E-ISSN 2046-2069, Vol. 4, no 37, p. 19061-19067Article in journal (Refereed)
    Abstract [en]

    Cellulose capsules with average outer and inner radii of approximately 44 mu m and 29 mm respectively were prepared from cellulose dissolved in a mixture of lithium chloride and dimethylacetamide using a microfluidic flow focusing device (MFFD). The MFFD had three inlets where octane oil in a cellulose solution in silicone oil was used to produce a double emulsion containing a cellulose capsule. This technique enables the formation of capsules with a narrow size distribution which can be beneficial for drug delivery or controlled release capsules. In this respect, cellulose is a highly interesting material since it is known to cause no autoimmune reactions when used in contact with human tissue. Furthermore, by controlling the chemical properties of the cellulose, it is possible to trigger a swelling of the capsules and consequentially the release of an encapsulated substance, e. g. a model drug, when the capsule becomes exposed to an external stimulus. To demonstrate this, capsules were functionalized by carboxymethylation to be pH- responsive and to expand approximately 10% when subjected to a change in pH from 3 to 10. The diffusion constant of a model drug, a 4 kDa fluorescently labelled dextran, through the native capsule wall was estimated to be 6.5 X 10(-14) m(2) s(-1) by fitting fluorescence intensity data to Fick's second law.

  • 12. Chen, Bin
    et al.
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Wu, Wenjun
    Zha, Quanzheng
    Xie, Yongshu
    A novel trigeminal zinc porphyrin and corresponding porphyrin monomers for dye-sensitized solar cells2014In: RSC Advances, E-ISSN 2046-2069, Vol. 4, no 21, p. 10439-10449Article in journal (Refereed)
    Abstract [en]

    A novel trigeminal zinc porphyrin sensitizer (T) and two zinc porphyrin monomers (M1 and M2) were successfully designed and synthesized. The spectral, electrochemical, and photovoltaic properties of the porphyrin dyes were investigated. Compared with M1, the molecule of M2 has an additional aliphatic n-hexyloxyl chain at the meso-position of the porphyrin framework, and such a structure is favorable for the formation of a compact hydrophobic layer at the TiO2 surface and the retardation of the diffusion of I-3(-) ions into the nanoporous TiO2 electrode, resulting in more effective suppression of the charge recombination process and a higher V-oc. Meanwhile, M2 has larger IPCE values than those of M1, leading to the higher J(sc) value. Thus, the DSSC devices based on M2 demonstrated a relatively high power conversion efficiency of 5.77%, with the J(sc), V-oc and ff values of 13.93 mA cm(-2), 732 mV, and 0.566, respectively. Even though dye T has the highest molar absorption coefficients and multiple binding moieties, the corresponding power conversion efficiency is 2.30%, which is lower than those for M1 and M2. These observations may be ascribed to the low efficiency of the electron injection process caused by the isolation of the LUMOs from the anchoring carboxyl groups in addition to the lowest adsorption amount.

  • 13. Chen, Cheng
    et al.
    Yang, Xichuan
    Cheng, Ming
    Zhang, Fuguo
    Zhao, Jianghua
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Highly efficient organic dyes containing a benzopyran ring as a pi-bridge for DSSCs2013In: RSC Advances, E-ISSN 2046-2069, Vol. 3, no 31, p. 12688-12693Article in journal (Refereed)
    Abstract [en]

    A series of novel organic dyes containing a benzopyran ring as a p-bridge have been designed and applied in dye-sensitized solar cells (DSSCs). This series of dyes show the excellent DSSCs' performance, due to their efficient light-to-photocurrent conversion in the region from 380 nm to 600 nm, with the highest IPCE values exceeding 90%. Through modification of the donor units, an efficiency as high as 7.5% has been achieved under standard light illumination (AM 1.5G, 100 mW cm(-2)) by the dye CC103.

  • 14.
    Chen, Fei
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Gällstedt, M.
    Olsson, Rickard
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Gedde, Ulf
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Hedenqvist, Mikael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    A novel chitosan/wheat gluten biofoam fabricated by spontaneous mixing and vacuum-drying2015In: RSC Advances, E-ISSN 2046-2069, Vol. 5, no 114, p. 94191-94200Article in journal (Refereed)
    Abstract [en]

    A new type of chitosan and wheat gluten biofoam is presented. The pore structure achieved relied solely on the specific mixing and phase distribution when a film was cast from an aqueous mixture of chitosan/wheat gluten solution, in the absence of any chemical blowing agent, porogen or expanding gas. The foam was obtained when the liquid phase was removed by vacuum drying, without the need for the traditional freeze-drying that is frequently used for pore formation. Soft foam samples could be prepared with stiffnesses from 0.3 to 1.2 MPa and a high rebound resilience (64 and 94% at compressive strains of 80 and 20%, respectively). The foams were relatively ductile and did not require any plasticiser to allow for in-plane deformation (20% compression) and smaller bending. Only open pores with sizes of the order of 70-80 μm were observed by microscopy. The density of all the foams was ∼50 kg m-3, due to the high porosity (96% air). The foams showed a rapid and large uptake of both non-polar (limonene) and polar (water) liquids. When immersed in these liquids for 1 second, the maximum uptake recorded was 40 times the initial mass of the foam for limonene and 8 times for water.

  • 15.
    Chen, Hui
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Montanari, Celine
    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.
    Yan, Max
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    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.
    Sychugov, Ilya
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Refractive index of delignified wood for transparent biocomposites2020In: RSC Advances, E-ISSN 2046-2069, Vol. 10, p. 40719-40724Article in journal (Refereed)
    Abstract [en]

    Refractive index (RI) determination for delignified wood templates is vital for transparent wood composite fabrication. Reported RIs in the literature are based on either single plant fibers or wood powder, measured by the immersion liquid method (ILM) combined with mathematical fitting. However, wood structure complexity and the physical background of the fitting were not considered. In this work, RIs of delignified wood templates were measured by the ILM combined with a light transmission model developed from the Fresnel reflection/refraction theory for composite materials. The RIs of delignified balsa wood are 1.536 ± 0.006 and 1.525 ± 0.008 at the wavelength of 589 nm for light propagating perpendicular and parallel to the wood fiber direction, respectively. For delignified birch wood, corresponding values are 1.537 ± 0.005 and 1.529 ± 0.006, respectively. The RI data for delignified wood scaffolds are important for tailoring optical properties of transparent wood biocomposites, and also vital in optical properties investigations by theoretical modelling of complex light propagation in transparent wood and related composites. The developed light transmission model in combination with the immersion liquid method can be used to determine the RI of complex porous or layered solid materials and composites.

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  • 16. Chen, S.
    et al.
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Song, L.
    A fluorescent photochromic diarylethene based on naphthalic anhydride with strong solvatochromism2017In: RSC Advances, E-ISSN 2046-2069, Vol. 7, no 47, p. 29854-29859Article in journal (Refereed)
    Abstract [en]

    A novel "push-pull" diarylethene molecule consisting of an electron withdrawing ethene bridge (1,8-naphthalic anhydride) and two moderate electron donating side chains (2,5-dimethylthiophene) has been designed and synthesized. The photochromism study, together with density functional theory calculations, revealed that the molecule exhibits reversible fluorescence switching capacity upon photo-isomerization and remarkable solvatochromism with red shift of the fluorescence maximum by more than 150 nm owing to intramolecular charge transfer.

  • 17. Chen, Shangjun
    et al.
    Li, Wenlong
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Zhu, Wei-Hong
    Substitution effect on the photochromic properties of benzo[b]thiophene-1,1-dioxide based diarylethenes2015In: RSC Advances, E-ISSN 2046-2069, Vol. 5, no 106, p. 87626-87634Article in journal (Refereed)
    Abstract [en]

    Benzo[b]thiophene-1,1-dioxide based diarylethenes (DAEs), BTT-1 to BTT-4, containing methyl, phenyl, formyl and triphenylamine groups at the 5,5'-position of the thiophene rings have been developed for gaining an insight into the substituent effect on the absorption and photochromic properties. Electron-donating substituents, such as phenyl and triphenylamine groups, are found to be effective at shifting the absorption band to a longer wavelength and decreasing the cyclization quantum yield. The electron-withdrawing formyl group can increase the cyclization quantum yield, but it reduces the thermal stability of the ring-closed isomer to some extent. BTT-4 bearing a triphenylamine group shows the poorest fatigue resistance among these four compounds, which is possibly due to the larger extended pi-conjugation length in the ring-closed isomer. BTT-2 bearing a phenyl unit undergoes typical photochromic reaction not only in solution, but also in PMMA thin film and in bulky crystals with excellent fatigue resistance and thermal stability.

  • 18. Chen, Wei
    et al.
    Zhang, Zhiyun
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Su, Jianhua
    Highly sensitive detection of low-level water content in organic solvents and cyanide in aqueous media using novel solvatochromic AIEE fluorophores2015In: RSC Advances, E-ISSN 2046-2069, Vol. 5, no 16, p. 12191-12201Article in journal (Refereed)
    Abstract [en]

    A great deal of effort has been devoted to develop easy-to-use fluorescent probes for detecting analytes due to their advantages in the field of chemo- and bio-sensing. Herein, two novel 2,2 '-biindenyl-based derivatives BDM and BDBM containing dicyanovinyl groups have been designed and synthesized, and are shown to possess the remarkable dual properties of solvatochromism and aggregation-induced emission enhancement (AIEE). Importantly, both of them are found to serve as fluorescent indicators for the qualitative and quantitative detection of low-level water in organic solvents. Meanwhile, both BDM and BDBM emit yellowish orange and orange fluorescence, respectively, in their aggregated states. Furthermore, with dicyanovinyl groups as the recognition sites, both compounds can act as colourimetric and fluorescent sensors for highly sensitive and selective detection of cyanide in aqueous media, and the apparent response signals can be observed by the naked eye even in the presence of various interference anions, promising practical applications for detecting cyanide in drinking water. Besides, optical spectroscopic techniques, NMR titration measurements, and density functional theory calculations are conducted to rationalize the sensing mechanisms of the two probes.

  • 19.
    Claudino, Mauro
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Thiol-ene coupling kinetics of D-limonene: a versatile 'non-click' free-radical reaction involving a natural terpene2013In: RSC Advances, E-ISSN 2046-2069, Vol. 3, no 27, p. 11021-11034Article in journal (Refereed)
    Abstract [en]

    The free-radical photoinduced thiol-ene reaction between D-limonene, as renewable diolefinic substrate, and two mono-/tri-functional thiols (iso-tridecyl 3-mercaptopropionate and trimethylolpropane tris(3-mercaptopropionate)), has been investigated kinetically to define a relationship between alkene structure and reactivity. Separate thiol-ene solutions of the appropriate thiol in d-chloroform, supplemented with 1.0 wt% of DMPA (Irgacure 651), were subjected to polychromatic UV-irradiation and the chemical changes monitored discontinuously via H-1 NMR spectroscopy to quantify double bond conversion. The kinetic concentration profiles were modeled analytically and simulated in the application software COPASI for parameter estimation and to verify if the experimental data explained a suggested mechanistic scheme. Empirical results demonstrate that the external vinylidene bond of limonene reacts about 6.5 times faster with thiol than the internal trisubstituted 1-methyl-cyclohexene unsaturation. The selectivity observed for the two unsaturations was successfully explained by means of a simplified steady-state equation derived from the sequential reaction mechanism accounting for propagation and chain-transfer elementary steps with estimated rate coefficients. Kinetic modeling results attribute the difference in selectivity partially to steric impediments controlling thiyl-radical insertion onto the double bonds and predominantly to differences in relative energy between the two tertiary insertion carbon radical intermediates. The rate-limiting step was identified as the third chain-transfer hydrogen-abstraction reaction promoted by the second insertion carbon radical intermediate. High thiol-ene conversions were obtained in a timely fashion without major influence of secondary reactions demonstrating the suitability of this reaction for network forming purposes. The mechanistic and kinetic information collected can be used as a quantitative predictive tool to assess the potential use of D-limonene in thiol-ene network forming systems involving multifunctional alkyl ester 3-mercaptopropionates.

  • 20.
    Claudino, Mauro
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Utilizing thiol-ene coupling kinetics in the design of renewable thermoset resins based on D-limonene and polyfunctional thiols2014In: RSC Advances, E-ISSN 2046-2069, Vol. 4, no 20, p. 10317-10329Article in journal (Refereed)
    Abstract [en]

    An extended model is developed to predict the free-radical thiol-ene reaction dynamics between D-limonene, as a renewable diolefin, and a monothiol compound (iso-tridecyl 3-mercaptopropionate) in bulk liquid conditions. Thermally and photo-initiated reactions of the two monomers showed favored thiol-ene coupling at the exo-isopropenyl alkene structure when reacted at 1 : 1 and 1 : 0.5 mole ratios. Experimental kinetic data obtained from the two stoichiometries were well reproduced numerically via the simulation software COPASI by introducing a multi-route mechanistic scheme with propagation-chain-transfer steps accounting for primary (mono-additions) and secondary (di-addition) modes of coupling. The differences in intrinsic double-bond reactivity enable synthesis of limonene-terminated resins (mono-versus poly-disperse) as multifunctional network precursors. Off-stoichiometry manipulations in the initial mole ratio, assisted by numerical simulations, offer a convenient approach to visualize the overall reaction system kinetics irrespective of temporal effects, thus being regarded as an important guiding tool for chemists aiming at designing thiol-ene systems based on limonene.

  • 21. Crespo, Gaston A.
    et al.
    Bakker, Eric
    Dynamic electrochemistry with ionophore based ion-selective membranes2013In: RSC Advances, E-ISSN 2046-2069, Vol. 3, no 48, p. 25461-25474Article in journal (Refereed)
  • 22.
    Dispenza, Clelia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. Università Degli Studi di Palermo, Italy.
    Sabatino, M. A.
    Grimaldi, N.
    Mangione, M. R.
    Walo, M.
    Murugan, Eagambaram
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    On the origin of functionalization in one-pot radiation synthesis of nanogels from aqueous polymer solutions2016In: RSC Advances, E-ISSN 2046-2069, Vol. 6, no 4, p. 2582-2591Article in journal (Refereed)
    Abstract [en]

    Radiation-engineered poly(N-vinyl pyrrolidone) nanogels are very interesting biocompatible nanocarriers for i.v. administration of therapeutics and contrast agents for bioimaging. The manufacturing process is fast and effective, it grants excellent control of particle size and simultaneous sterilization of the formed nanogels. Interestingly, primary amino groups and carboxyl groups, useful for (bio) conjugation, are also formed in a dose-dependent fashion. In this paper, by means of both numerical simulations and experiments, the origin of nanogel size control and functionalization is investigated. This understanding offers a new dimension for the design and production of radiation-sculptured multifunctional nanocarriers from aqueous solutions of polymers.

  • 23. Dobrota, Ana S.
    et al.
    Gutic, Sanjin
    Kalijadis, Ana
    Baljozovic, Milos
    Mentus, Slavko V.
    Skorodumova, Natalia V.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Uppsala Univ, Sweden.
    Pasti, Igor A.
    Stabilization of alkali metal ions interaction with OH-functionalized graphene via clustering of OH groups - implications in charge storage applications2016In: RSC Advances, E-ISSN 2046-2069, Vol. 6, no 63, p. 57910-57919Article in journal (Refereed)
    Abstract [en]

    Graphene synthesized by reduction of graphene oxide, depending on the degree of reduction, retains a certain amount of surface OH groups. Considering the surface OH groups/graphene layer system by means of density functional theory calculations, we evidenced the tendency of OH groups to cluster, resulting in enhanced system stability and no band gap opening. In the oxygen concentration range between 1.8 and 8.47 at%, with the addition of each new OH group, integral binding energy decreases, while differential binding energy shows the boost at even numbers of OH groups. Furthermore, we found that the clustering of OH groups over graphene basal plane plays a crucial role in enhancing the interactions with alkali metals. Namely, if alkali metal atoms interact with individual OH groups only, the interaction leads to an irreversible formation of MOH phase. When alkali atoms interact with clusters containing odd number of OH groups, a reversible transfer of an electron charge from the metal atom to the substrate takes place without OH removal. The strength of the interaction in general increases from Li to K. In an experimental investigation of a graphene sample which dominantly contains OH groups, we have shown that the trend in the specific interaction strength reflects to gravimetric capacitances measured in alkali metal chloride solutions. We propose that the charge stored in OH groups which interact with alkali metal cation and the pi electronic system of the graphene basal plane presents the main part of its pseudocapacitance.

  • 24.
    El-Seedi, Hesham R.
    et al.
    Uppsala Univ, Biomed Ctr, Dept Med Chem, Pharmacognosy Grp, Box 574, SE-75123 Uppsala, Sweden.;Jiangsu Univ, Coll Food & Biol Engn, Zhenjiang 212013, Jiangsu, Peoples R China.;Al Rayan Coll, Al Rayan Res & Innovat Ctr, Medina 42541, Saudi Arabia.;Menoufia Univ, Fac Sci, Dept Chem, Al Minufiyah, Egypt..
    El-Shabasy, Rehan M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry. Menoufia Univ, Fac Sci, Dept Chem, Al Minufiyah, Egypt.
    Khalifa, Shaden A. M.
    Karolinska Univ Hosp, Clin Res Ctr, Huddinge, Sweden.;Stockholm Univ, Wenner Gren Inst, Dept Mol Biosci, SE-10691 Stockholm, Sweden..
    Saeed, Aamer
    Quaid I Azam Univ, Dept Chem, Islamabad 45320, Pakistan..
    Shah, Afzal
    Univ Bahrain, Coll Sci, Dept Chem, Sakhir 32038, Bahrain..
    Shah, Raza
    Univ Karachi, Int Ctr Chem & Biol Sci, HEJ Res Inst Chem, Karachi 75270, Pakistan..
    Iftikhar, Faiza Jan
    Quaid I Azam Univ, Dept Chem, Islamabad 45320, Pakistan..
    Abdel-Daim, Mohamed M.
    Suez Canal Univ, Fac Vet Med, Pharmacol Dept, Ismailia 41522, Egypt..
    Omri, Abdelfatteh
    KAU, Ctr Excellence Bionosci Res, Jeddah 21589, Saudi Arabia.;KAU, Dept Biol Sci, Biotechnol Res Grp, Fac Sci, Jeddah 21589, Saudi Arabia..
    Hajrahand, Nahid H.
    KAU, Ctr Excellence Bionosci Res, Jeddah 21589, Saudi Arabia.;KAU, Dept Biol Sci, Biotechnol Res Grp, Fac Sci, Jeddah 21589, Saudi Arabia..
    Sabir, Jamal S. M.
    KAU, Ctr Excellence Bionosci Res, Jeddah 21589, Saudi Arabia.;KAU, Dept Biol Sci, Biotechnol Res Grp, Fac Sci, Jeddah 21589, Saudi Arabia..
    Zou, Xiaobo
    Jiangsu Univ, Coll Food & Biol Engn, Zhenjiang 212013, Jiangsu, Peoples R China..
    Halabi, Mohammed F.
    Al Rayan Coll, Al Rayan Res & Innovat Ctr, Medina 42541, Saudi Arabia..
    Sarhan, Wessam
    Zewail City Sci & Technol, Cairo, Egypt..
    Guo, Weisheng
    Guangzhou Med Univ, Affiliated Hosp 2, Translat Med Ctr, Guangzhou 510260, Guangdong, Peoples R China..
    Metal nanoparticles fabricated by green chemistry using natural extracts: biosynthesis, mechanisms, and applications2019In: RSC Advances, E-ISSN 2046-2069, Vol. 9, no 42, p. 24539-24559Article, review/survey (Refereed)
    Abstract [en]

    Nanoparticles (NPs) are new inspiring clinical targets that have emerged from persistent efforts with unique properties and diverse applications. However, the main methods currently utilized in their production are not environmentally friendly. With the aim of promoting a green approach for the synthesis of NPs, this review describes eco-friendly methods for the preparation of biogenic NPs and the known mechanisms for their biosynthesis. Natural plant extracts contain many different secondary metabolites and biomolecules, including flavonoids, alkaloids, terpenoids, phenolic compounds and enzymes. Secondary metabolites can enable the reduction of metal ions to NPs in eco-friendly one-step synthetic processes. Moreover, the green synthesis of NPs using plant extracts often obviates the need for stabilizing and capping agents and yields biologically active shape- and size-dependent products. Herein, we review the formation of metallic NPs induced by natural extracts and list the plant extracts used in the synthesis of NPs. In addition, the use of bacterial and fungal extracts in the synthesis of NPs is highlighted, and the parameters that influence the rate of particle production, size, and morphology are discussed. Finally, the importance and uniqueness of NP-based products are illustrated, and their commercial applications in various fields are briefly featured.

  • 25. Emam, A. N.
    et al.
    Mohamed, M. B.
    Girgis, E.
    Rao, K. Venkat
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Hybrid magnetic-plasmonic nanocomposite: Embedding cobalt clusters in gold nanorods2015In: RSC Advances, E-ISSN 2046-2069, Vol. 5, no 44, p. 34696-34703Article in journal (Refereed)
    Abstract [en]

    We developed a method to fabricate hybrid magnetic-plasmonic nanorods (Au-Co NRs) via a modified seed mediated method. The only modification is to use cobalt ions instead of Au3+ in the preparation of the seed solution to obtain gold nanorods doped with Co clusters. By adjusting the amount of cobalt seed solution, Au-Co NRs of controlled aspect ratio can be obtained. The optical properties of the obtained Au-Co NRs were investigated and compared to those of the pure Au NRs. A slight shift and broadening were observed in the alloys compared to the pure ones, which was attributed to the presence of Co clusters leading to suppression of the dielectric properties. High resolution transmission electron microscopy (HRTEM) images indicate the existence of Co clusters in situ in the Au NR host and clearly show the metal-metal interface. The magnetic properties of the obtained Au-Co NRs increase as the concentration of dopant Co cluster seeds increases, as investigated by vibrating sample magnetometry (VSM). Our approach allows us to design nanomaterials of controlled shape, optical and magnetic properties which have many promising applications in tharanostics and photoelectronics.

  • 26. Endrodi, Balazs
    et al.
    Mellar, J.
    Gingl, Z.
    Visy, C.
    Janaky, C.
    Reasons behind the improved thermoelectric properties of poly(3-hexylthiophene) nanofiber networks2014In: RSC Advances, E-ISSN 2046-2069, Vol. 4, no 98, p. 55328-55333Article in journal (Refereed)
    Abstract [en]

    Enhanced thermoelectric properties of poly(3-hexylthiophene) nanofiber networks, doped in their reaction with silver cations, are presented. The role of charge carrier concentration and mobility (influenced by the supramolecular structure and nanoscale morphology) is discussed. The nanonet structure leads to a six fold increase in the ZT value compared to the bulk polymer counterpart.

  • 27.
    Esquivel-Pena, Vicente
    et al.
    Univ Nacl Autonoma Mexico, Dept Quim Analit, Fac Quim, Ciudad Univ, Mexico City 04510, DF, Mexico..
    Guccini, Valentina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Stockholm Univ, Dept Mat & Environm Chem, Arrhenius Lab, SE-10691 Stockholm, Sweden..
    Kumar, Sugam
    Stockholm Univ, Dept Mat & Environm Chem, Arrhenius Lab, SE-10691 Stockholm, Sweden..
    Salazar-Alvarez, German
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Stockholm Univ, Dept Mat & Environm Chem, Arrhenius Lab, SE-10691 Stockholm, Sweden..
    de San Miguel, Eduardo Rodriguez
    Univ Nacl Autonoma Mexico, Dept Quim Analit, Fac Quim, Ciudad Univ, Mexico City 04510, DF, Mexico..
    de Gyves, Josefina
    Univ Nacl Autonoma Mexico, Dept Quim Analit, Fac Quim, Ciudad Univ, Mexico City 04510, DF, Mexico..
    Hybrids based on borate-functionalized cellulose nanofibers and noble-metal nanoparticles as sustainable catalysts for environmental applications2020In: RSC Advances, E-ISSN 2046-2069, Vol. 10, no 21, p. 12460-12468Article in journal (Refereed)
    Abstract [en]

    Polymeric supports from renewable resources such as cellulose nanomaterials are having a direct impact on the development of heterogenous sustainable catalysts. Recently, to increase the potentiality of these materials, research has been oriented towards novel functionalization possibilities. In this study, to increase the stability of cellulose nanofiber films as catalytic supports, by limiting the solubility in water, we report the synthesis of new hybrid catalysts (HC) based on silver, gold, and platinum nanoparticles, and the corresponding bimetallic nanoparticles, supported on cellulose nanofibers (CNFs) cross-linked with borate ions. The catalysts were prepared from metal precursors reduced by the CNFs in an aqueous suspension. Metal nanoparticles supported on CNFs with a spherical shape and a mean size of 9 nm were confirmed by TEM, XRD, and SAXS. Functionalized films of HC-CNFs were obtained by adding a borate solution as a cross-linking agent. Solid-state B-11 NMR of films with different cross-linking degrees evidenced the presence of four different boron species of which the bis-chelate is responsible for the cross-linking of the CNFs. Also, it may be concluded that the bis-chelate and the mono-chelates modify the microstructure of the film increasing the water uptake and enhancing the catalytic activity in the reduction of 4-nitrophenol.

  • 28.
    Fang, Mei
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Aristov, Andrey
    Rao, K. Venkat
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Kabashin, Andrei V.
    Belova, Lyubov
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Particle-free inkjet printing of nanostructured porous indium tin oxide thin films2013In: RSC Advances, E-ISSN 2046-2069, Vol. 3, no 42, p. 19501-19507Article in journal (Refereed)
    Abstract [en]

    We report a simple, low-cost, single-step inkjet printing method for the fabrication of nanostructured, highly transparent and conductive ITO films, which completely avoids the use of ITO particles in the fabrication process. In our method, the inks are formed from a liquid solution presenting a properly selected mixture of indium and tin acetates. After jet printing, the ink is decomposed during a subsequent annealing step, in which the released CO2 gas bubbles control the ITO nucleation process to provide a porous film texture. We show that the fabricated ITO films are highly crystalline, stoichiometric, and nanoporous with controlled porosity. Electrical measurements show relatively low resistivity values for the films (down to 0.029 Omega cm) comparable to those of the best ITO thin films fabricated by other methods. Optical ellipsometry tests demonstrate a relatively high refractive index (1.5-1.7) and high transparency of the films over a wide region of the spectrum ranging from 500 to 1700 nm. Since the method does not require any pre-fabricated ITO particles, masks or templates, and enables the deposition of films on substrates of various materials and shapes, it can be employed for fabrication of nanoporous ITO films for a diversity of applications, including solar cell, bio- and chemical sensing, etc.

  • 29.
    Farahani, Pooria
    et al.
    Instituto de Química, Departamento de Química Fundamental, Universidade de São Paulo, São Paulo, SP, Brazil.
    Oliveira, Marcelo
    Fdez. Galvan, Ignacio
    Baader, Wilhelm J.
    A combined theoretical and experimental study onthe mechanism of spiro-adamantyl-1,2-dioxetanone decomposition2017In: RSC Advances, E-ISSN 2046-2069, Vol. 7, p. 17462-17472Article in journal (Refereed)
    Abstract [en]

    1,2-Dioxetanones have been considered as model compounds for bioluminescence processes. Theunimolecular decomposition of these prototypes leads mainly to the formation of triplet excited stateswhereas in the catalysed decomposition of these peroxides singlet states are formed preferentially.Notwithstanding, these cyclic peroxides are important models to understand the general principles ofchemiexcitation as they can be synthesised, purified and characterised. We report here results ofexperimental and theoretical approaches to investigating the decomposition mechanism of spiroadamantyl-1,2-dioxetanone. The activation parameters in the unimolecular decomposition of thisderivative have been determined by isothermal kinetic measurements (30–70 C) and thechemiluminescence activation energy calculated from the correlation of emission intensities. Theactivation energy for peroxide decomposition proved to be considerably lower than thechemiluminescence activation energy indicating the existence of different reaction pathways for groundand excited state formation. These experimental results are compared with the calculations at thecomplete active space second-order perturbation theory (CASPT2), which reveal a two-step biradicalmechanism starting by weak peroxide bond breakage followed by carbon–carbon elongation. Thetheoretical findings also indicate different transition state energies on the excited and ground statesurfaces during the C–C bond cleavage in agreement with the experimental activation parameters.

  • 30.
    Finnveden, Maja
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Brännström, Sara
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Johansson, Mats
    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.
    Martinelle, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Novel sustainable synthesis of vinyl ether ester building blocks, directly from carboxylic acids and the corresponding hydroxyl vinyl ether, and their photopolymerization2018In: RSC Advances, E-ISSN 2046-2069, Vol. 8, no 44, p. 24716-24723Article in journal (Refereed)
    Abstract [en]

    Increased environmental awareness has led to a demand for sustainable, bio-based materials. Consequently, the development of new benign synthesis pathways utilizing a minimum of reaction steps and available bio-based building blocks is needed. In the present study, vinyl ether alcohols and functional carboxylic acids were used to synthesize bifunctional vinyl ether esters using the immobilized enzyme Candida antarctica lipase B as a catalyst. Vinyl ethers are attractive alternatives to (meth)acrylates due to low allergenic hazards, low toxicity, and fast polymerization; however, difficult synthesis limits the monomer availability. The synthesis was performed in one-pot and the described method was successful within a broad temperature range (22-90 degrees C) and in various organic solvents as well as in the bulk. The synthesis of different vinyl ether esters reached high conversions (above 90%) after less than 1 h and products were purified by removing the enzyme by filtration using only small amounts of acetone. This approach is a straightforward route to reach monomers with multiple types of functionalities that can be used as different photo-curable thermoset resins. In this work, this was demonstrated by polymerizing the monomers with cationic and radical UV-polymerization. By changing the functional carboxylic acids, the architecture of the final polymer can be tailored, herein demonstrated by two examples. In the developed versatile method, carboxylic acids can be used directly as acyl donors, constituting a more sustainable alternative to the carboxylic acid derivatives used today.

  • 31.
    Forsberg, Viviane
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. Mid Sweden Univ, FSCN, Surface & Colloid Engn, Holmgatan 10, SE-85170 Sundsvall, Sweden..
    Maslik, Jan
    Tomas Bata Univ Zlin, Ctr Polymer Syst, Trida Tomase Bati 5678, CZ-76001 Zlin, Czech Republic..
    Norgren, Magnus
    Mid Sweden Univ, FSCN, Surface & Colloid Engn, Holmgatan 10, SE-85170 Sundsvall, Sweden..
    Electronic performance of printed PEDOT:PSS lines correlated to the physical and chemical properties of coated inkjet papers2019In: RSC Advances, E-ISSN 2046-2069, Vol. 9, no 41, p. 23925-23938Article in journal (Refereed)
    Abstract [en]

    PEDOT:PSS organic printed electronics chemical interactions with the ink-receiving layer (IRL) of monopolar inkjet paper substrates and coating color composition were evaluated through Raman spectroscopy mapping in Z (depth) and (XY) direction, Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray spectroscopy (EDS). Other evaluated properties of the IRLs were pore size distribution (PSD), surface roughness, ink de-wetting, surface energy and the impact of such characteristics on the electronics performance of the printed layers. Resin-coated inkjet papers were compared to a multilayer coated paper substrate that also contained an IRL but did not contain the plastic polyethylene (PE) resin layer. This substrate showed better electronic performance (i.e., lower sheet resistance), which we attributed to the inert coating composition, higher surface roughness and higher polarity of the surface which influenced the de-wetting of the ink. The novelty is that this substrate was rougher and with somewhat lower printing quality but with better electronic performance and the advantage of not having PE in their composite structure, which favors recycling.

  • 32.
    Giummarella, Nicola
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Wallenberg Wood Science Center.
    Zhang, Liming
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Henriksson, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Wallenberg Wood Science Center.
    Lawoko, Martin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Wallenberg Wood Science Center.
    Structural features of mildly fractionated lignin carbohydrate complexes (LCC) from spruce2016In: RSC Advances, E-ISSN 2046-2069, Vol. 6, no 48, p. 42120-42131Article in journal (Refereed)
    Abstract [en]

    A protocol for the quantitative fractionation of lignin carbohydrate complexes (LCC) from wood under mild conditions has been developed. All operations occur at near-neutral pH conditions and low temperatures, in order to preserve the native structure. The protocol also achieved the fractionation of hemicelluloses of relatively high purity enabling for the first time estimates of hemicelluloses fractions not chemically bound to lignin in wood. 2D HSQC NMR was applied to decipher the structure of LCCs and was complemented by thioacidolysis-GC MS techniques. The carbohydrates linked to lignin in LCC are hemicelluloses, mainly arabinoglucuronoxylan (AGX) and galactoglucomannan (GGM). Benzylether (BE) and phenyl glycosidic (PG) linkages were detected. Significant structural differences in the lignin part of LCCs are also reported. The novelty of this work is that we report the first quantitative pH neutral protocol for LCC fractionation and detailed chemical analyses unveil important structural differences of relevance to fundamental knowledge in lignin polymerization and wood-based biorefineries.

  • 33. Golda-Cepa, M.
    et al.
    Aminlashgari, Nina
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Engvall, Klas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Kotarba, A.
    LDI-MS examination of oxygen plasma modified polymer for designing tailored implant biointerfaces2014In: RSC Advances, E-ISSN 2046-2069, Vol. 4, no 50, p. 26240-26243Article in journal (Refereed)
    Abstract [en]

    A versatile polymer coating for biomaterials was fabricated by the mild oxygen plasma treatment of Chemical Vapour Deposited (CVD) parylene C. The surface properties were tailored while the excellent protective properties of the bulk were preserved. The species, formed due to the plasma functionalisation, were fingerprinted by a novel Laser Desorption/Ionisation-Mass Spectrometry (LDI-MS) method. Improved osteosarcoma cells (line MG-63) attachment and viability on a modified surface were demonstrated.

  • 34. Golda-Cepa, M.
    et al.
    Engvall, Klas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Kotarba, A.
    Development of crystalline-amorphous parylene C structure in micro-and nano-range towards enhanced biocompatibility: the importance of oxygen plasma treatment time2015In: RSC Advances, E-ISSN 2046-2069, Vol. 5, no 60, p. 48816-48821Article in journal (Refereed)
    Abstract [en]

    The crystalline-amorphous parylene C structure was fabricated by Chemical Vapour Deposited (CVD) and functionalised in the micro- and nano-range with the oxygen plasma treatment. The evolution of thermal stability, structure and surface biocompatibility of parylene C films as an effect of oxygen plasma treatment time were evaluated by means of thermogravimetric/differential thermal analysis (TG/DTA), X-Ray Diffraction (XRD) and cells adhesion tests (crystal violet assay, fluorescence microscopy). The results are epitomized by a crystalline-amorphous parylene C structural model. It was found that the time of oxygen plasma treatment is critical for adhesion of osteoblast cells with the optimum of 5-8 minutes.

  • 35.
    Gowda, Vasantha
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Biler, Michal
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Filippov, Andrei
    Luleå Univ Technol, Chem Interfaces, Luleå, Sweden.;Kazan State Med Univ, Dept Med & Biol Phys, Kazan 420012, Russia..
    Mantonico, Malisa, V
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Ornithopoulou, Eirini
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Linares, Mathieu
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Linköping Univ, Lab Organ Elect, S-60174 Norrköping, Sweden.;Linköping Univ, Grp Sci Visualizat, ITN, S-60174 Norrköping, Sweden.;Linköping Univ, Swedish E Sci Res Ctr SeRC, S-60174 Norrköping, Sweden..
    Antzutkin, Oleg N.
    Luleå Univ Technol, Chem Interfaces, Luleå, Sweden.;Univ Warwick, Dept Phys, Coventry, W Midlands, England..
    Lendel, Christofer
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Structural characterisation of amyloid-like fibrils formed by an amyloidogenic peptide segment of beta-lactoglobulin2021In: RSC Advances, E-ISSN 2046-2069, Vol. 11, no 45, p. 27868-27879Article in journal (Refereed)
    Abstract [en]

    Protein nanofibrils (PNFs) represent a promising class of biobased nanomaterials for biomedical and materials science applications. In the design of such materials, a fundamental understanding of the structure-function relationship at both molecular and nanoscale levels is essential. Here we report investigations of the nanoscale morphology and molecular arrangement of amyloid-like PNFs of a synthetic peptide fragment consisting of residues 11-20 of the protein beta-lactoglobulin (beta-LG(11-20)), an important model system for PNF materials. Nanoscale fibril morphology was analysed by atomic force microscopy (AFM) that indicates the presence of polymorphic self-assembly of protofilaments. However, observation of a single set of C-13 and N-15 resonances in the solid-state NMR spectra for the beta-LG(11-20) fibrils suggests that the observed polymorphism originates from the assembly of protofilaments at the nanoscale but not from the molecular structure. The secondary structure and inter-residue proximities in the beta-LG(11-20) fibrils were probed using NMR experiments of the peptide with C-13- and N-15-labelled amino acid residues at selected positions. We can conclude that the peptides form parallel beta-sheets, but the NMR data was inconclusive regarding inter-sheet packing. Molecular dynamics simulations confirm the stability of parallel beta-sheets and suggest two preferred modes of packing. Comparison of molecular dynamics models with NMR data and calculated chemical shifts indicates that both packing models are possible.

  • 36.
    Gusev, Alexey
    et al.
    Russian Acad Sci, NS Kurnakov Inst Gen & Inorgan Chem, Moscow 119991, Russia. ryukova, Mariya.
    Braga, Elena
    Zamnius, Ekaterina
    Kiskin, Mikhail
    Kryukova, Mariya
    Baryshnikova, Alina
    Minaev, Boris F.
    Bohdan Khmelnytsky Natl Univ, Dept Chem & Nanomat Sci, UA-18031 Cherkassy, Ukraine.
    Baryshnikov, Gleb V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Bohdan Khmelnytsky Natl Univ, Dept Chem & Nanomat Sci, UA-18031 Cherkassy, Ukraine.
    Ågren, Hans
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Linert, Wolfgang
    Structure and excitation-dependent emission of novel zinc complexes with pyridyltriazoles2019In: RSC Advances, E-ISSN 2046-2069, Vol. 9, no 38, p. 22143-22152Article in journal (Refereed)
    Abstract [en]

    A series of Zn(ii) complexes with 5-(4-R-phenyl)-3-(pyridin-2-yl)-1,2,4-triazoles have been synthesized and subsequently characterized by single crystal X-ray diffraction, H-1-NMR, FT-IR spectroscopy, elemental analyses, ESI-MS, and PXRD. The X-ray diffraction analyses revealed that the complexes have a similar molecular structure and their supramolecular frameworks are constructed by hydrogen bonds and pi center dot center dot center dot pi interaction scaffolds. Upon irradiation with UV light, the studied complexes display deep blue emission at 396-436 nm in the solid state. The compounds show an unexpected excitation-dependent emission phenomenon which is detected by a change in the emission color (from blue to yellow) upon increase of the excitation wavelength. The conducted quantum-chemical calculations indicate that supramolecular differences in the single-crystal architecture of the synthesized complexes play a crucial role for this photophysical behaviour.

  • 37. Ha, Minh Ngoc
    et al.
    Zhu, Feng
    Liu, Zhifu
    Wang, Lichao
    Liu, Linyan
    Lu, Guanzhong
    Zhao, Zhe
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Shanghai Institute of Technology, China.
    Morphology-controlled synthesis of SrTiO3/TiO2 heterostructures and their photocatalytic performance for water splitting2016In: RSC Advances, E-ISSN 2046-2069, Vol. 6, no 25, p. 21111-21118Article in journal (Refereed)
    Abstract [en]

    Different morphologies of SrTiO3/TiO2 heterostructures like nanocubes, nanoparticles, nanospheres, and nanofibers were synthesized via a facile hydrothermal process using TiO2 as both a template and precursor in Sr(OH)(2) solution. Their structure, interface and composition can be rationally tailored by simply adjusting the Sr(OH)(2)/TiO2 (Sr/Ti) mole ratios and the morphology of SrTiO3/TiO2 heterostructures can be controlled easily using TiO2 with different morphologies. A SrTiO3 crystal thin layer was grown on an anatase TiO2 substrate to fabricate a heterostructure interface contact between SrTiO3 and TiO2 and the lattice mismatch had an effect on the electrical transport properties. The SrTiO3/TiO2 heterostructures are beneficial for the fast separation of photogenerated electrons and holes so as to suppress the recombination of photogenerated electrons and holes at the interface of SrTiO3 and TiO2. Besides this, the different morphologies of the SrTiO3/TiO2 heterostructures allowing facile electron transfer, the hierarchical structure promoting mass transfer and allowing more light reflection and absorption, and the large specific surface area providing more reaction sites to facilitate the reactants to the desired oxidation places all together create a synergistic effect to improve the photocatalytic activity of the hierarchical SrTiO3/TiO2 heterostructures. Under the irradiation of UV light, in a water/methanol sacrificial reagent system, the SrTiO3/TiO2 NP heterostructures at a Sr/Ti mole ratio of 40% with the highest BET and smallest crystallite size achieve the highest photocatalytic activity generating 0.731 mmol of H-2. The SrTiO3/TiO2 heterostructures exhibit better photocatalytic activity by generating three times more H-2 than bare TiO2 and pure SrTiO3.

  • 38.
    Hassanzadeh, Salman
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Adolfsson, Karin H.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Controlling the cooperative self-assembly of graphene oxide quantum dots in aqueous solutions2015In: RSC Advances, E-ISSN 2046-2069, Vol. 5, no 71, p. 57425-57432Article in journal (Refereed)
    Abstract [en]

    Fascinating 3D cooperative self-assembly behavior was observed for 2D graphene oxide quantum dots (GOQDs) in dilute and semi dilute aqueous solutions. In addition the optical properties could be tuned by controlling the supramolecular structures. While the electrostatic interactions between the charged single sheets were assigned as the main secondary interactions that were responsible for the supramolecular fine structures, the concentration, temperature, salt concentration and pH could tune the repulsive/attractive forces and the molecular binding between the GOQD sheets. The morphological studies combined with UV-Vis and fluorescence evaluations proved that after a slow nucleation step, elongation preceded radially by H-aggregate self-association of the GOQD monomers, forming the final porous spheres by radial growth of rods. The quenching properties of the self-associated-assembled GOQDs together with the excitation wavelengths of the GOQD solutions enabled tuning of the fluorescence intensity and color of the final solutions, which could be utilized for e.g. bioimaging and smart spectroscopy.

  • 39.
    Hatton, Fiona
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. University of Sheffield, United Kingdom.
    Engström, Joakim
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Forsling, Josefine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Carlmark, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Biomimetic adsorption of zwitterionic-xyloglucan block copolymers to CNF: towards tailored super-absorbing cellulose materials2017In: RSC Advances, E-ISSN 2046-2069, Vol. 7, no 24, p. 14947-14958Article in journal (Refereed)
    Abstract [en]

    A biomimetic, facile approach to cellulose modification is the utilisation of self-adsorbing, naturally occurring biopolymers, such as the hemicellulose xyloglucan (XG). Herein, XG-block-poly(sulfobetaine methacrylate) (XG-b-PSBMA) zwitterionic block copolymers have been prepared and assessed for their ability to adsorb to cellulose, specifically cellulose nanofibrils (CNF). The polymers were synthesised using reversible addition-fragmentation chain-transfer (RAFT) polymerisation, employing an XG macromolecular RAFT agent (XG-RAFT), polymerising a sulfobetaine methacrylate (SBMA) under aqueous conditions. The incorporation of the XG block shifted the upper critical solution temperature (UCST) values to higher temperatures (20 and 30 °C) compared with the PSBMA homopolymers (17 and 22 °C) and the transition was also broadened. The adsorption of the polymers to a CNF surface was monitored using quartz crystal microbalance with dissipation monitoring (QCM-D), showing that the XG block enhanced the adsorption of the zwitterionic polymer. The formation of CNF-composite films was achieved utilising a facile vacuum filtration methodology, and the targeted compositions were confirmed by FT-IR and TGA analyses. The films exhibited high degrees of swelling in water, which were investigated at two different temperatures, 5 and 60 °C (below and above the polymer USCT values). These results highlight the advantage of using an XG block for the biomimetic modification of cellulose to form new cellulose-composite materials such as super-absorbing films.

  • 40.
    Hayat, Anwer
    et al.
    Zhejiang Univ, Coll Opt Sci & Engn, Natl Engn Res Ctr Opt Instruments, Hangzhou 310058, Peoples R China..
    Alamgir,
    Huang, Liangai
    Zhejiang Univ, Coll Opt Sci & Engn, Natl Engn Res Ctr Opt Instruments, Hangzhou 310058, Peoples R China.;Taizhou Agil Smart Technol Co Ltd, Taizhou, Zhejiang, Peoples R China..
    Wang, Zongpeng
    Zhejiang Univ, Coll Opt Sci & Engn, Natl Engn Res Ctr Opt Instruments, Hangzhou 310058, Peoples R China.;Taizhou Agil Smart Technol Co Ltd, Taizhou, Zhejiang, Peoples R China..
    Ullah, Raza
    Qingdao Univ, Coll Mat Sci & Engn, Qingdao 266071, Peoples R China..
    He, Sailing
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering and Fusion Science. Zhejiang Univ, Coll Opt Sci & Engn, Natl Engn Res Ctr Opt Instruments, Hangzhou 310058, Peoples R China.
    One-pot in situ synthesis of an NS-ligand co-doped metal-organic framework for the enhanced adsorption-assisted photocatalytic decontamination of metronidazole2024In: RSC Advances, E-ISSN 2046-2069, Vol. 14, no 15, p. 10229-10243Article in journal (Refereed)
    Abstract [en]

    Doping active agents into metal-organic frameworks (MOFs) is widely sought after owing to its potential to enhance adsorption and photocatalytic efficiency, surpassing the potential of bare frameworks. This study incorporated a catalytically active NS-ligand (1,2-benzisothiazolin-3-one) into a very stable and porous PCN-600 MOF via an in situ synthesis approach. The NS-ligand, which matched with the host ligands of PCN-600, enabled the highly efficient synthesis of NS-co-doped MOFs. The pristine PCN-600 framework and morphology were retained in the MOF altered with the NS-ligand, as demonstrated by XRD, FTIR, and SEM characterizations. A high electron density was generated due to the synergistic effect between the defects in the NS-co-doped photocatalyst and engineered active sites. This facilitated the adsorption-assisted photocatalytic decontamination of metronidazole with an 87% removal by PCN-600-NS-10 compared to 43% by pristine PCN-600 within a total time of 150 min. The MOF doped with the NS-ligand exhibited a reduced band gap and enhanced adsorption and photocatalytic capabilities compared to pristine PCN-600. The impact of operational parameters, such as catalyst dosage, initial solution pH, and MNZ concentration, was also explored. Pseudo-second and pseudo-first order models were found to describe the adsorption and degradation kinetics of metronidazole and the Dubinin-Radushkevich model was found to fit the equilibrium adsorption results. The thermodynamic characteristics of adsorption processes (Delta G(ads), Delta H-ads, and Delta S-ads) demonstrated that adsorption was physical, spontaneous, and exothermic and resulted in increased entropy.

  • 41.
    He, Xie
    et al.
    Zhejiang Univ, Natl Engn Res Ctr Opt Instruments, Ctr Opt & Electromagnet Res, Hangzhou 310058, Peoples R China..
    Cao, Qijie
    Zhejiang Univ, Natl Engn Res Ctr Opt Instruments, Ctr Opt & Electromagnet Res, Hangzhou 310058, Peoples R China..
    Pan, Jing
    Zhejiang Univ, Natl Engn Res Ctr Opt Instruments, Ctr Opt & Electromagnet Res, Hangzhou 310058, Peoples R China..
    Yang, Liu
    Zhejiang Univ, Natl Engn Res Ctr Opt Instruments, Ctr Opt & Electromagnet Res, Hangzhou 310058, Peoples R China.;Zhejiang Univ, Ningbo Res Inst, Ningbo 315100, Peoples R China..
    He, Sailing
    KTH, School of Engineering Sciences (SCI), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. Zhejiang Univ, Natl Engn Res Ctr Opt Instruments, Ctr Opt & Electromagnet Res, Hangzhou 310058, Peoples R China.;Zhejiang Univ, Ningbo Res Inst, Ningbo 315100, Peoples R China..
    Patterned few nanometer-thick silver films with high optical transparency and high electrical conductivity2021In: RSC Advances, E-ISSN 2046-2069, Vol. 11, no 19, p. 11481-11489Article in journal (Refereed)
    Abstract [en]

    Transparent conductive electrodes (TCEs) are experimentally demonstrated using patterned few nanometer-thick silver films on zinc oxide-coated rigid and flexible substrates. The grid lines are completely continuous, but only 8.4 nm thick. This is the thinnest metallic grid we are aware of. Owing to the high transparency of both the grid lines and spacing, our TCE with an opening ratio (OR) as small as 36% achieves an average optical transmittance up to similar to 90% in the visible regime, breaking the optical limits of both the unpatterned film counterpart and the thick grid counterpart (whose optical transmittance is determined by the OR). The small OR enables a low sheet resistance of similar to 21.5 omega sq(-1). The figure of merit up to similar to 17 k omega(-1) is superior to those of the unpatterned film counterpart, our fabricated 180 nm thick ITO, as well as most reported thick metal grid TCEs. Our ultrathin TCE, firmly attached to the substrate, is mechanically more flexible and more stable than the film counterpart and ITO. As a flexible transparent film heater, it achieves comparable or even superior heating performances with previously-reported heaters and performs well in a thermochromic test.

  • 42. Hermans, J. J.
    et al.
    Keune, K.
    Van Loon, A.
    Corkery, Robert W.
    KTH.
    Iedema, P. D.
    Ionomer-like structure in mature oil paint binding media2016In: RSC Advances, E-ISSN 2046-2069, Vol. 6, no 96, p. 93363-93369Article in journal (Refereed)
    Abstract [en]

    Infrared spectra of samples from oil paintings often show metal carboxylate bands that are broader and shifted compared to those of crystalline metal soap standards (metal complexes of long-chain saturated fatty acids). Using quantitative attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), it is demonstrated that the broad metal carboxylate band is typically too intense to be explained by carboxylates adsorbed on the surface of pigment particles or disordered metal complexes of saturated fatty acids. The metal carboxylate species associated with the broad bands must therefore be an integral part of the polymerized binding medium. Small-angle X-ray scattering (SAXS) measurements on model ionomer systems based on linseed oil revealed that the medium contains ionic clusters similar to more classical ionomers. These structural similarities are very helpful in understanding the chemistry of mature oil paint binding media and the potential degradation mechanisms that affect oil paintings.

  • 43. Hong, Tao
    et al.
    Song, Heli
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Zhang, Weibing
    Xie, Yongshu
    Syntheses of mono- and diacylated bipyrroles with rich substitution modes and development of a prodigiosin derivative as a fluorescent Zn(II) probe2014In: RSC Advances, E-ISSN 2046-2069, Vol. 4, no 12, p. 6133-6140Article in journal (Refereed)
    Abstract [en]

    The acylation of 2,20-bipyrrole with pentafluorobenzoyl chloride in the presence of AlCl3 afforded six acylated products with rich alpha-, beta-, beta(1)-, alpha,alpha'-, alpha,beta(')-, and alpha,beta(1)'-substitution modes for 1-6, respectively. Then, the alpha,alpha'-diacylated compound 4 was used to synthesize a prodigiosin derivative 9, which provides an alternative method for the syntheses of prodigiosin derivatives. Crystal structures of 1, 4 and 9 show interesting supramolecular dimers formed by multiple hydrogen bonds, O...pi interactions, as well as pi... pi interactions. Interestingly, 9 shows fluorescence turn-on probing behavior towards Zn2+ both in DMF and in DMF-HEPES, with high sensitivity and selectivity. The detection limit for Zn2+ in DMF was calculated to be 1.1 x 10(-8) M.

  • 44. Hu, M.
    et al.
    Yu, Z.
    Li, J.
    Jiang, X.
    Lai, J.
    Yang, X.
    Wang, M.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Low-cost solution-processed digenite Cu9S5 counter electrode for dye-sensitized solar cells2017In: RSC Advances, E-ISSN 2046-2069, Vol. 7, no 61, p. 38452-38457Article in journal (Refereed)
    Abstract [en]

    The development of low-cost alternatives to the commonly used but expensive platinum (Pt) catalyst in dye-sensitized solar cells (DSSCs) is important from a commercial point of view. In this work, Cu9S5 nanocrystalline film is fabricated directly onto a F-doped SnO2 (FTO) substrate by a solution-processed spin-coating method with low temperature post-treatment at 250 °C and it is further explored as a counter electrode (CE) material in DSSCs. The results from cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) disclose that Cu9S5 film exhibits a higher catalytic ability for the state-of-the-art cobalt(ii/iii) tris(bipyridyl) ([Co(bpy)3]2+/3+) redox system as compared to the widely used iodine-based electrolyte. Consequently, the DSSC devices based on the cobalt complex redox shuttles show a power conversion efficiency (PCE) of 5.7% measured at 100 mW cm-2 illumination (AM 1.5G), which is substantially higher than that of the iodine-based counterpart (3.9%). This has been the first presentation for the application of digenite copper sulfides as an electrocatalyst for the [Co(bpy)3]2+/3+ redox system in DSSCs. The present finding represents a promising solution for the development of alternative cost-effective CE materials for DSSCs in the future.

  • 45.
    Hua, Geng
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Olsen, Peter
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Franzén, Johan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Odelius, Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Anionic polycondensation and equilibrium driven monomer formation of cyclic aliphatic carbonates2018In: RSC Advances, E-ISSN 2046-2069, Vol. 8, no 68, p. 39022-39028Article in journal (Refereed)
    Abstract [en]

    The current work explores the sodium hydride mediated polycondensation of aliphatic diols with diethyl carbonate to produce both aliphatic polycarbonates and cyclic carbonate monomers. The lengths of the diol dictate the outcome of the reaction; for ethylene glycol and seven other 1,3-diols with a wide array of substitution patterns, the corresponding 5-membered and 6-membered cyclic carbonates were synthesized in excellent yield (70-90%) on a 100 gram scale. Diols with longer alkyl chains, under the same conditions, yielded polycarbonates with an M-w ranging from 5000 to 16000. In all cases, the macromolecular architecture revealed that the formed polymer consisted purely of carbonate linkages, without decarboxylation as a side reaction. The synthetic design is completely solvent-free without any additional post purification steps and without the necessity of reactive ring-closing reagents. The results presented within provide a green and scalable approach to synthesize both cyclic carbonate monomers and polycarbonates with possible applications within the entire field of polymer technology.

  • 46.
    Huang, Fuhua
    et al.
    Hunan Provincial Key Laboratory of Environmental Catalysis & Waste Recycling, College of Materials and Chemical Engineering, Hunan Institute of Engineering, Xiangtan 411104 P. R. China; Henan Center for Outstanding Overseas Scientists, Henan University, KaiFeng 475004 P. R. China; College of Chemistry and Molecular Sciences, Henan University, KaiFeng Henan 475004 P. R. China, Henan; Henan Key Laboratory of Protection and Safety Energy Storage of Light Metal Materials, Henan University, KaiFeng Henan 475004 P. R. China, Henan.
    Liu, Cong
    Henan Center for Outstanding Overseas Scientists, Henan University, KaiFeng 475004 P. R. China; College of Chemistry and Molecular Sciences, Henan University, KaiFeng Henan 475004 P. R. China, Henan; Henan Key Laboratory of Protection and Safety Energy Storage of Light Metal Materials, Henan University, KaiFeng Henan 475004 P. R. China, Henan.
    Zhao, Zhuoya
    Henan Center for Outstanding Overseas Scientists, Henan University, KaiFeng 475004 P. R. China; College of Chemistry and Molecular Sciences, Henan University, KaiFeng Henan 475004 P. R. China, Henan; Henan Key Laboratory of Protection and Safety Energy Storage of Light Metal Materials, Henan University, KaiFeng Henan 475004 P. R. China, Henan.
    Wang, Li
    Henan Center for Outstanding Overseas Scientists, Henan University, KaiFeng 475004 P. R. China; College of Chemistry and Molecular Sciences, Henan University, KaiFeng Henan 475004 P. R. China, Henan; Henan Key Laboratory of Protection and Safety Energy Storage of Light Metal Materials, Henan University, KaiFeng Henan 475004 P. R. China, Henan.
    Zhang, Jinglai
    Henan Center for Outstanding Overseas Scientists, Henan University, KaiFeng 475004 P. R. China; College of Chemistry and Molecular Sciences, Henan University, KaiFeng Henan 475004 P. R. China, Henan; Henan Key Laboratory of Protection and Safety Energy Storage of Light Metal Materials, Henan University, KaiFeng Henan 475004 P. R. China, Henan.
    Ågren, Hans
    Henan Center for Outstanding Overseas Scientists, Henan University, KaiFeng 475004 P. R. China; College of Chemistry and Molecular Sciences, Henan University, KaiFeng Henan 475004 P. R. China, Henan; Henan Key Laboratory of Protection and Safety Energy Storage of Light Metal Materials, Henan University, KaiFeng Henan 475004 P. R. China, Henan.
    Widengren, Jerker
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum and Biophotonics.
    Liu, Haichun
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum and Biophotonics.
    Morphology controlled synthesis of Fe3+-doped upconversion nanomaterials2024In: RSC Advances, E-ISSN 2046-2069, Vol. 14, no 8, p. 4990-5000Article in journal (Refereed)
    Abstract [en]

    This work details the synthesis of paramagnetic upconversion nanoparticles doped with Fe3+ in various morphologies via the thermal decomposition method, followed by comprehensive characterization of their structures, optical properties and magnetism using diverse analytical techniques. Our findings demonstrate that by precisely modulating the ratio of oleic acid to octadecene in the solvent, one can successfully obtain hexagonal nanodiscs with a consistent and well-defined morphology. Further adjustments in the oleic acid to octadecene ratio, coupled with fine-tuning of the Na+/F− ratio, led to the production of small-sized nanorods with uniform morphology. Significantly, all Fe3+-doped nanoparticles displayed pronounced paramagnetism, with magnetic susceptibility measurements at 1 T and room temperature of 0.15 emu g−1 and 0.14 emu g−1 for the nanodiscs and nanorods, respectively. To further enhance their magnetic properties, we replaced the Y-matrix with a Gd-matrix, and by fine-tuning the oleic acid/octadecene and Na+/F− ratios, we achieved nanoparticles with uniform morphology. The magnetic susceptibility was 0.82 emu g−1 at 1 T and room temperature. Simultaneously, we could control the nanoparticle size by altering the synthesis temperature. These upconversion nanostructures, characterized by both paramagnetic properties and regular morphology, represent promising dual-mode nanoprobe candidates for optical biological imaging and magnetic resonance imaging.

  • 47.
    Hutchinson, Daniel J.
    et al.
    Department of Chemistry, University of Otago.
    Hanton, Lyall R.
    Department of Chemistry, University of Otago.
    Moratti, Stephen C.
    Department of Chemistry, University of Otago.
    The one pot synthesis of heterobimetallic complexes from a homoditopic pyrimidine–hydrazone ligand2014In: RSC Advances, E-ISSN 2046-2069, Vol. 4, no 28, p. 14550-14556Article in journal (Refereed)
    Abstract [en]

    The symmetrical, homoditopic, pyrimidine-hydrazone (pym-hyz) ligand L1 was used to synthesise three new heterobimetallic complexes, CuPbL1(ClO4)4, CuAgL1(SO3CF3)3, and CuZnL1(SO3CF3)4. Each of the complexes was produced in a one-pot reaction in CH3CN, and was isolated in high yield and purity simply by precipitation through the addition of diethyl ether. Analysis was carried out by IR, UV-Vis and ESMS spectroscopy, as well as microanalysis. Crystals were also grown for the purposes of X-ray diffraction studies, which yielded the structures [CuPbL1(ClO4)(CH3CN)2(H2O)](ClO4)3(1),[CuAgL1(SO3CF3)(CH3CN)2](SO3CF3)2$CH3CN (2), and CuZnL1(SO3CF3)2(CH3CN)(H2O)](SO3CF3)2$CH3CN (3), all of which were linear complexes containing a Cu(II) ion in one of the pym-hyz-py coordination sites, and either a Pb(II), Ag(I), or Zn(II) ion in the other.

  • 48.
    Håkansson, Karl
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Online determination of anisotropy during cellulose nanofibril assembly in a flow focusing device2015In: RSC Advances, E-ISSN 2046-2069, Vol. 5, no 24, p. 18601-18608Article in journal (Refereed)
    Abstract [en]

    In order to utilize the high strength (ultimate tensile strength = 3 GPa) [Saito et al., Biomacromolecules, 2012, 14, 248] and stiffness (Young's modulus = 130 GPa) [Sakurada et al., J. Polym. Sci., 1962, 57, 651] of cellulose nanofibrils in a macroscopic material or composite, the structure of the elongated fibrils in the material must be controlled. Here, cellulose nanofibrils in a dispersed state are partly aligned in a flow focusing device, whereafter the anisotropic nano-structure is locked by a dispersion-gel transition. The alignment process has been studied by Hakansson et al., [Nat. Commun., 2014, 5, 4018], however, the location of the phase transition as well as at which alignment (anisotropy) the fibrils were locked was not investigated. In this study, the degree of alignment is determined with small angle X-ray scattering experiments and the location of the phase change is measured with polarized light experiments. Furthermore, the anisotropy of the hydrogel thread is determined and the thread is seen to still be anisotropic after six months in a water bath.

  • 49. Höglin, Viktor
    et al.
    Cedervall, Johan
    Andersson, Mikael Svante
    Sarkar, Tapati
    Hudl, Matthias
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF. Uppsala University, Uppsala, Sweden.
    Nordblad, Per
    Andersson, Yvonne
    Sahlberg, Martin
    Phase diagram, structures and magnetism of the FeMnP1-xSix-system2015In: RSC Advances, E-ISSN 2046-2069, Vol. 5, no 11, p. 8278-8284Article in journal (Refereed)
    Abstract [en]

    The magnetic properties of the (Fe,Mn)(2)(P,Si)-system have been shown to be readily manipulated by small changes in composition. This study surveys the FeMnP1-xSix-system (0.00 <= x <= 1.00) reporting sample syntheses and investigations of crystallographic and magnetic properties using X-ray powder diffraction and magnetic measurements. Two single phase regions exist: the orthorhombic Co2P-type structure (x < 0.15) and the Fe2P-type structure (0.24 <= x < 0.50). Certain compositions have potential for use in magnetocaloric applications.

  • 50.
    Iranmanesh, Ida Sadat
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Ramachandraiah, Harisha
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Russom, Aman
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Wiklund, Martin
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    On-chip ultrasonic sample preparation for cell based assays2015In: RSC Advances, E-ISSN 2046-2069, Vol. 5, no 91, p. 74304-74311Article in journal (Refereed)
    Abstract [en]

    We demonstrate an acoustophoresis method for size-based separation, isolation, up-concentration and trapping of cells that can be used for on-chip sample preparation combined with high resolution imaging for cell-based assays. The method combines three frequency-specific acoustophoresis functions in a sequence by actuating three separate channel zones simultaneously: zones for pre-alignment, size-based separation, and trapping. We characterize the mutual interference between the acoustic radiation forces between the different zones by measuring the spatial distribution of the acoustic energy density during different schemes of ultrasonic actuation, and use this information for optimizing the driving frequencies and voltages of the three utilized ultrasonic transducers attached to the chip, and the flow rates of the pumps. By the use of hydrodynamic defocusing of the pre-aligned cells in the separation zone, a cell population from a complex sample can be isolated and trapped with very high purity, followed by dynamic fluorescence analysis. We exemplify the method's potential by isolating A549 lung cancer cells from red blood cells with 100% purity, 92% separation efficiency, and 93% trapping efficiency resulting in a 130× up-concentration factor during 15 minutes of continuous sample processing through the chip. Furthermore, we demonstrate an on-chip fluorescence assay of the isolated cancer cells by monitoring the dynamic uptake and release of a fluorescence probe in individual trapped cells. The ability to combine isolation of individual cells from a complex sample with high-resolution image analysis holds great promise for applications in cellular and molecular diagnostics.

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