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  • 151.
    Lo Re, Giada
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Engström, Joakim
    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, Coating Technology.
    Wu, Qiong
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Malmström, Eva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Gedde, Ulf W
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Olsson, Richard
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymeric Materials.
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Improved Cellulose Nanofibril Dispersion in Melt-Processed Polycaprolactone Nanocomposites by a Latex-Mediated Interphase and Wet Feeding as LDPE Alternative2018In: ACS Applied Nano Materials, Vol. 1, no 6, p. 2669-2677Article in journal (Refereed)
    Abstract [en]

    This work reports the development of a sustainable and green one-step wet-feeding method to prepare tougher and stronger nanocomposites from biodegradable cellulose nanofibrils (CNF)/polycaprolactone (PCL) constituents, compatibilized with reversible addition fragmentation chain transfer-mediated surfactant-free poly(methyl methacrylate) (PMMA) latex nanoparticles. When a PMMA latex is used, a favorable electrostatic interaction between CNF and the latex is obtained, which facilitates mixing of the constituents and hinders CNF agglomeration. The improved dispersion is manifested in significant improvement of mechanical properties compared with the reference material. The tensile tests show much higher modulus (620 MPa) and strength (23 MPa) at 10 wt % CNF content (compared to the neat PCL reference modulus of 240 and 16 MPa strength), while maintaining high level of work to fracture the matrix (7 times higher than the reference nanocomposite without the latex compatibilizer). Rheological analysis showed a strongly increased viscosity as the PMMA latex was added, that is, from a well-dispersed and strongly interacting CNF network in the PCL.

  • 152.
    Lousada, Cláudio M.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Technology.
    Fernandes, Ricardo M. F.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Tarakina, Nadezda V.
    Soroka, Inna L.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Synthesis of copper hydride (CuH) from CuCO3·Cu(OH)2 – a path to electrically conductive thin films of Cu2017In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 46, no 20, p. 6533-6543Article in journal (Refereed)
    Abstract [en]

    The most common synthesis methods for copper hydride (CuH) employ hard ligands that lead to the formation of considerable amounts of metallic Cu as side-product. Here we explore a synthesis method for CuH(s) through the reaction of CuCO3 center dot Cu(OH)(2)(s) with hypophosphorous acid (H3PO2) in solution, via the formation of the intermediate Cu(H2PO2)(2)(aq) complex. The reaction products were characterized with XRD, FTIR and SEM at different reaction times, and the kinetics of the transformation of Cu(H2PO2)(2)(aq) to CuH(s) were followed with NMR and are discussed. We show that our synthesis method provides a simple way for obtaining large amounts of CuH(s) even when the synthesis is performed in air. Compared to the classic Wurtz method, where CuSO4 is used as an initial source of Cu2+, our synthesis produces CuH particles with less metallic Cu side-product. We attribute this to the fact that our reaction medium is free from the hard SO42- ligand that can disproportionate Cu(I). We discuss a mechanism for the reaction based on the known reactivity of the reagents and intermediates involved. We explored the possibility of using CuH(s) for making electrically conductive films. Tests that employed water-dispersed CuH particles show that this compound can be reduced with H3PO2 leading to electrically conductive thin films of Cu. These films were made on regular office paper and were found to be Ohmic conductors even after several weeks of exposure to ambient conditions. The fact that the synthesis reported here produces large amounts of CuH particles in aqueous media, with very little impurities, and the fact that these can then be converted to a stable electrically conductive film can open up new applications for CuH such as for printing electrically conductive films or manufacturing surface coatings.

  • 153.
    Lousada, Cláudio M.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Technology.
    Johansson, Adam Johannes
    Korzhavyi, Pavel A.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Technology.
    Molecular and dissociative adsorption of water and hydrogen sulfide at perfect and defective Cu(110) surfaces2017In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, p. 8111-8120Article in journal (Refereed)
    Abstract [en]

    We performed a density functional theory (DFT) investigation of the molecular and dissociative adsorption of H2O and H2S at perfect and defective Cu(110) surfaces described using supercells with c(6 × 6) periodicity. The defective surface consists of a terrace surrounded by pits. We found considerable differences in adsorption modes and energies for H2O and H2S. At the defective Cu(110) surface, monomers of H2O and H2S preferentially adsorb at the terrace site and molecular adsorption of H2O is significantly more favorable than that of H2S. For dissociative adsorption however, the sulfur species are considerably more stable than the oxygen species. For monolayer (ML) coverages, there are small differences in the molecular adsorption energies for H2O and H2S. However, for the formation of 1 ML of HO and 1 ML of HS from 1 ML of H2O and 1 ML of H2S, respectively, with the release of H2(g), the differences are very large. The formation of 1 ML HO at the perfect Cu(110) surface is endoergic, while at the defective Cu(110) surface it is exoergic by −0.6 eV. For high coverages, H2S forms stacked half-monolayers that interact with each other via a complex hydrogen bond network with a strength per H2S molecule of −0.140 eV per H2S and −0.120 eV per H2S for H2S located in the underlayer and overlayer, respectively. The large distances between hydrogen bonded H2S molecules explain the preference for the formation of the two stacked half-monolayers of H2S instead of a single monolayer as it happens with H2O. Additionally, the formation of 1 ML of HS does not occur because of the spontaneous splitting of some H–S bonds resulting in surface bound HS and S and H2S molecules. Extensive surface reconstruction and relaxation accompanies adsorption of the sulfur adsorbates. Such reconstructions with outwards pull of Cu atoms can be at the origin of the weak adhesion of sulfide films that explains the release of CuS particles from copper sulfide films at copper surfaces. Overall, the surface defects here investigated induce non-linear effects in the molecular and dissociative adsorption energies of different O and S adsorbates.

  • 154.
    Lousada, Cláudio M.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Technology.
    Johansson, Adam Johannes
    Korzhavyi, Pavel A.
    Molecular and dissociative adsorption of water at a defective Cu(110) surface2017In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 658, p. 1-8Article in journal (Refereed)
    Abstract [en]

    We performed a density functional theory (DFT) investigation of the molecular and dissociative adsorption of water at the perfect Cu(110) and at a defective Cu surface that provides a broad spectrum of adsorption sites in terms of coordination of Cu atoms, with the aim of understanding the role of surface defects in the dissociation of water molecules. The molecular adsorption of water is spontaneous at both surfaces but at the defective surface we found two stable molecular adsorption structures that differ slightly in the disposition of the O-atoms of H2O on the surface plane but differ considerably on the orientation of their H-atoms. Additionally we studied the dissociative adsorption of water accompanied with formation of H2(g). At the defective surface, starting from 1 ML of molecularly adsorbed H2O, the dissociation of 0.22 ML of H2O leading to 0.22 ML of HO, 0.78 ML H2O and H2(g) is exergonic but the dissociation of 0.44 ML or more H2O molecules is endergonic. These findings are discussed in terms of the two main factors that affect the adsorption energies: the existence of exposed adatoms provides an environment that facilitates the interaction with small adsorbates leading to stronger bonds between the surface and such adsorbates; and at the same time, the limited polarizability of the defect sites causes high coverages of adsorbates that drag electron density from the surface to be unfavorable. The overall effect is that at the defective Cu(110) formation of low coverages of HO groups is more favorable than at the perfect Cu(110) while forming coverages higher than 0.44 ML of HO is less favorable than at the perfect Cu(110). These effects have their origin in the extent of the polarization of the Cu–O bonds.

  • 155.
    Lousada Patrício, Cláudio Miguel
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Reactions of aqueous radiolysis products with oxide surfaces: An experimental and DFT study2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The reactions between aqueous radiolysis products and oxide surfaces are important in nuclear technology in many ways. In solid-liquid systems, they affect (and at the same time are dependent on) both the solution chemistry and the stability of materials under the influence of ionizing radiation. The stability of surface oxides is a factor that determines the longevity of the materials where such oxides are formed. Additionally, the aqueous radiolysis products are responsible for corrosion and erosion of the materials.

      In this study, the reactions between radiolysis products of water – mainly H2O2 and HO radicals – with metal, lanthanide and actinide oxides are investigated. For this, experimental and computational chemistry methods are employed. For the experimental study of these systems it was necessary to implement new methodologies especially for the study of the reactive species – the HO radicals. Similarly, the computational study also required the development of models and benchmarking of methods. The experiments combined with the computational chemistry studies produced valuable kinetic, energetic and mechanistic data.

      It is demonstrated here that the HO radicals are a primary product of the decomposition of H2O2. For all the materials, the catalytic decomposition of H2O2 consists first of molecular adsorption onto the surfaces of the oxides. This step is followed by the cleavage of the O-O bond in H2O2 to form HO radicals. The HO radicals are able to react further with the hydroxylated surfaces of the oxides to form water and a surface bound HO center. The dynamics of formation of HO vary widely for the different materials studied. These differences are also observed in the activation energies and kinetics for decomposition of H2O2. It is found further that the removal of HO from the system where H2O2 undergoes decomposition, by means of a scavenger, leads to the spontaneous formation of H2.

      The combined theoretical-experimental methodology led to mechanistic understanding of the reactivity of the oxide materials towards H2O2 and HO radicals. This reactivity can be expressed in terms of fundamental properties of the cations present in the oxides. Correlations were found between several properties of the metal cations present in the oxides and adsorption energies of H2O, adsorption energies of HO radicals and energy barriers for H2O2 decomposition. This knowledge can aid in improving materials and processes important for nuclear technological systems, catalysis, and energy storage, and also help to better understand geochemical processes.

  • 156.
    Lu, Huiran
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Leijonmarck, Simon
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry. Swerea KIMAB AB.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Cornell, Ann M.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Flexible Paper Electrodes for Li-Ion Batteries Using Low Amount of TEMPO-Oxidized Cellulose Nanofibrils as Binder2016In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, no 28, p. 18097-18106Article in journal (Refereed)
    Abstract [en]

    Flexible Li-ion batteries attract increasing interest for applications in bendable and wearable electronic devices. TEMPO-oxidized cellulose nanofibrils (TOCNF), a renewable material, is a promising candidate as binder for flexible Li-ion batteries with good mechanical properties. Paper batteries can be produced using a water-based paper making process, avoiding the use of toxic solvents. In this work, finely dispersed TOCNF was used and showed good binding properties at concentrations as low as 4 wt %. The TOCNF was characterized using atomic force microscopy and found to be well dispersed with fibrils of average widths of about 2.7 nm and lengths of approximately 0.1-1 mu m. Traces of moisture, trapped in the hygroscopic cellulose, is a concern when the material is used in Li-ion batteries. The low amount of binder reduces possible moisture and also increases the capacity of the electrodes, based on total weight. Effects of moisture on electrochemical battery performance were studied on electrodes dried at 110 degrees C in a vacuum for varying periods. It was found that increased drying time slightly increased the specific capacities of the LiFePO4 electrodes, whereas the capacities of the graphite electrodes decreased. The Coulombic efficiencies of the electrodes were not much affected by the varying drying times. Drying the electrodes for 1 h was enough to achieve good electrochemical performance. Addition of vinylene carbonate to the electrolyte had a positive effect on cycling for both graphite and LiFePO4. A failure mechanism observed at high TOCNF concentrations is the formation of compact films in the electrodes.

  • 157.
    Lu, Huiran
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Hagberg, Johan
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Cornell, Ann
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Li4Ti5O12 flexible, lightweight electrodes based on cellulose nanofibrils as binder and carbon fibers as current collectors for Li-ion batteries2017In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 39, p. 140-150Article in journal (Refereed)
    Abstract [en]

    TEMPO oxidized cellulose nanofibrils (TOCNF) were used as binder material to prepare bendable Li4Ti5O12 (LTO) electrodes. Carbon fiber (CF) layers were integrated as current collectors to enhance the mechanical properties and to increase the specific energy of the electrodes. These electrodes combined with CF current collectors (LTO/CF) show good electrochemical properties and are flexible, sustainable, mechanical and chemical stable, lightweight and produced by a water-based easy filtration process. An increase of the active material weight (LTO) from around 19% to 71% of the electrode and current collector combined weight is demonstrated with CF compared with a copper current collector. Additionally, preparation of the current collector material is non-expensive, quick and easy compared to that of carbon nanotube or graphene. To test the flexible battery application, 4000 times repeated bending was carried out on both the LTO electrodes and the LTO/CF electrodes. This had no significant effect on the morphology, mechanical and electrochemical properties of neither the LTO nor the LTO/CF electrodes. Addition of the CF layer improves the mechanical properties and specific capacity of the LTO-electrode. A thicker LTO electrode with only 2 wt% TOCNF is demonstrated which is promising for thicker electrodes with high energy density. A full cell was assembled with the LTO/CF as negative electrode and LiFePO4 (LFP)/CF as positive, which exhibited a stable cycling performance and good energy density.

  • 158. Lu, Zhansheng
    et al.
    Yang, Zongxian
    Hermansson, Kersti
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Castleton, Christopher W. M.
    Several different charge transfer and Ce3+ localization scenarios for Rh-CeO2(111)2014In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 2, no 7, p. 2333-2345Article in journal (Refereed)
    Abstract [en]

    We present DFT+U based electronic structure calculations in a p(3 x 3) slab supercell, for low coverages of atomically dispersed Rh interacting with the CeO2(111) surface, comparing Rh as an adatom, and as a dopant substituted into the surface layer. We find that, energetically, a Rh atom approaching a ceria(111) surface with both sparse O and Ce vacancies present strongly prefers to heal the Ce vacancies, but next it prefers to adsorb on a stoichiometric region rather than healing an O vacancy. In the adatom system, Rh is oxidized by electron transfer to a 4f orbital on one Ce ion in the surface layer, which is then nominally converted from Ce4+ -> Ce3+ (i.e. Rh adatoms are single donors). We show that there are a number of different local minima, with Ce3+ localization at 1st, 2nd or 3rd nearest neighbour Ce sites. The second neighbour is the most stable, but all are close in energy. In the Rh-doped system (Rh replaces Ce), Rh is oxidized by charge transfer to neighbouring O atoms, and Rh doping leads to deep acceptor and donor states. Rh is not stable in the O sublattice. Moreover, based on vacancy formation energies, we find that oxygen vacancy formation is strongly enhanced in the vicinity of Rh dopants, but slightly suppressed in the vicinity of Rh adatoms.

  • 159.
    Lundblad, Anders
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Materials characterization of thin film electrodes for PEFC - Survey of methods and an example2004In: Journal of New Materials for Electrochemical Systems, ISSN 1480-2422, Vol. 7, no 1, p. 21-28Article in journal (Refereed)
    Abstract [en]

    Thorough materials characterization is an essential tool for obtaining a deeper understanding of the electrochemical processes taking place in thin film electrodes of polymer fuel cells. This paper gives a survey of different methods for characterizing materials properties that are relevant to the electrochemical performance of such electrodes (i.e. loading, thickness, electrical conductivity, porosity, pore size distribution and pore morphology). The use of these materials characterization methods is exemplified, among other things it is shown that the ionomer (Nafion(R)) in a thin-film electrode made by the spraying method is homogeneously distributed in pores smaller than 40 nm. Furthermore, the ionomer penetrates and/or encapsulates the primary carbon particles of 30 nm. The results are discussed in relation to different MEA fabrication methods.

  • 160.
    Luo, T.
    et al.
    Aix Marseille Univ, Fac St Jerome, CNRS, IM2NP, Case 142, F-13397 Marseille 20, France..
    Mangelinck, D.
    Aix Marseille Univ, Fac St Jerome, CNRS, IM2NP, Case 142, F-13397 Marseille 20, France..
    Descoins, M.
    Aix Marseille Univ, Fac St Jerome, CNRS, IM2NP, Case 142, F-13397 Marseille 20, France..
    Bertoglio, M.
    Aix Marseille Univ, Fac St Jerome, CNRS, IM2NP, Case 142, F-13397 Marseille 20, France..
    Mouaici, N.
    Ecole Natl Mines & Met ENSMM Annaba, Ex CEFOS Chaiba BP 233 RP Annaba,W129, Sidi Amar, Algeria..
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT).
    Girardeaux, C.
    Aix Marseille Univ, Fac St Jerome, CNRS, IM2NP, Case 142, F-13397 Marseille 20, France..
    Combined effect of Pt and Walloying elements on Ni-silicide formation2018In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 123, no 12, article id 125301Article in journal (Refereed)
    Abstract [en]

    A combinatorial study of the combined effect of Pt and W on Ni silicide formation is performed. Ni(Pt, W) films with thickness and composition gradients were prepared by a co-deposition composition spread technique using sputtering deposition from Pt, W, and Ni targets. The deposited Ni(Pt, W) films were characterized by X-ray diffraction, X-ray reflectivity, Rutherford backscattering, and atom probe tomography. The maximum content of alloying elements is close to 27 at. %. Simulations of the thickness and composition were carried out and compared with experimental results. In situ X-ray diffraction and atom probe tomography were used to study the phase formation. Both additive alloying elements (Pt + W) slow down the Ni consumption and the effect of W is more pronounced than the one of Pt. Regarding the effect of alloying elements on Ni silicides formation, three regions could be distinguished in the Ni(Pt, W)/Si wafer. For the region close to the Ni target, the low contents of alloying elements (Pt + W) have little impact on the phase sequence (delta-Ni2Si is the first silicide and NiSi forms when Ni is entirely consumed) but the kinetics of silicide formation slows down. The region close to the Pt target has high contents of (Pt + W) and is rich in Pt and a simultaneous phase formation of delta-Ni(2)Sii and NiSi is observed. For the high (PtthornW) contents and W-rich region, NiSi forms unexpectedly before delta-Ni2Si and the subsequent growth of delta-Ni2Si is accompanied by the NiSi consumption. When Ni is entirely consumed, NiSi regrows at the expense of delta-Ni2Si.

  • 161.
    Lyne, Bruce
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Commercially available nanomaterials for inclusion in forest products2011In: TAPPI Int. Conf. Nanotechnology Renew. Mater., 2011, p. 944-956Conference paper (Refereed)
  • 162.
    Ma, Ying
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Ceria-based Nanostructured Materials for Low-Temperature Solid Oxide Fuel Cells2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    As one of the most efficient and environmentally benign energy conversion devices, solid oxide fuel cells (SOFC) have attracted much attention in recent years. Conventional SOFC with yttria-stabilized zirconia as electrolyte require high operation temperature (800-1000 °C), which causes significant problems like material degradation, as well as other technological complications and economic barrier for wider applications. Therefore, there is a broad interest in reducing the operation temperature of SOFCs. One of the most promising ways to develop low-temperature SOFCs (LTSOFC) is to explore effective materials for each component with improved properties. So in this thesis, we are aiming to design and fabricate ceria-based nanocomposite materials for electrolyte and electrodes of LTSOFC by a novel nanocomposite approach.

    In the first part of the thesis, novel core-shell doped ceria/Na2CO3 nanocomposite was fabricated and investigated as electrolytes materials of LTSOFC. Two types of doped ceria were selected as the main phase for nanocomposite: samarium doped ceria (SDC) and calcium doped ceria (CDC). The core-shell SDC/Na2CO3 nanocomposite particles are smaller than 100 nm with amorphous Na2CO3 shell of 4~6 nm in thickness. The ionic conductivity of nanocomposite electrolytes were investigated by EIS and four-probe d.c. method, which demonstrated much enhanced ionic conductivities compared to the single phase oxides. The thermal stability of such nanocomposite has also been investigated based on XRD, BET, SEM and TGA characterization after annealing samples at various temperatures. Such nanocomposite was applied in LTSOFCs with an excellent power density of 0.8 Wcm-2 at 550 °C. The high performances together with notable thermal stability prove the doped ceria/Na2CO3 nanocomposite as a potential electrolyte material for long-term LTSOFCs.

    In the second part of the thesis, a novel template-, surfactant-free chemical synthetic route has been successfully developed for the controlled synthesis of hierarchically structured CeO2 with nanowires and mesoporous microspheres morphologies. The new synthetic route was designed by utilizing the chelate formation between cerium ion and various carboxylates forms of citric acid. Then, hierarchically structured cerium oxide with morphologies of nanowires and mesoporous microspheres can be obtained by thermal decomposition of the two kinds of precursors. Moreover, by doping with desired elements, SDC nanowires and SDC-CuO mesoporous microspheres were prepared and used for electrolyte and anode materials, respectively, based on their unique properties depending on their morphologies. When SDC nanowires/Na2CO3 composite were applied as electrolyte for single SOFC, and it exhibited maximum power density of 522 mWcm-2 at 600 °C, which is much better than the state-of-the-art SOFCs using doped ceria as electrolytes. Besides, the mesoporous CuO-SDC composite anode was synthesized by our microwave-assisted method, which shows good phase homogeneity of both SDC and CuO. When it was applied for fuel cells, the cell had better performance than conventional CuO-SDC anode prepared by solid state method.

    The whole work of this thesis aims to provide a new methodology for the entire SOFC community. It is notable that our work has attracted considerable attention after publication of several attached papers. The results in this thesis may benefit the development of LTSOFC and expand the related research to a new horizon.

  • 163. Malti, Abdellah
    et al.
    Edberg, Jesper
    Granberg, Hjalmar
    Khan, Zia Ullah
    Andreasen, Jens W.
    Liu, Xianjie
    Zhao, Dan
    Zhang, Hao
    Yao, Yulong
    Brill, Joseph W.
    Engquist, Isak
    Fahlman, Mats
    Wågberg, Lars
    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.
    Crispin, Xavier
    Berggren, Magnus
    An Organic Mixed Ion-Electron Conductor for Power Electronics2016In: Advanced Science, ISSN 2198-3844, Vol. 3, no 2, article id UNSP 1500305Article in journal (Refereed)
    Abstract [en]

    A mixed ionic–electronic conductor based on nanofibrillated cellulose composited with poly(3,4-ethylene-dioxythio­phene):­poly(styrene-sulfonate) along with high boiling point solvents is demonstrated in bulky electrochemical devices. The high electronic and ionic conductivities of the resulting nanopaper are exploited in devices which exhibit record values for the charge storage capacitance (1F) in supercapacitors and transconductance (1S) in electrochemical transistors.

  • 164. Marino, T.
    et al.
    Boerrigter, M.
    Faccini, M.
    Chaumette, C.
    Arockiasamy, L.
    Bundschuh, Jochen
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Figoli, A.
    Photocatalytic activity and synthesis procedures of TiO2 nanoparticles for potential applications in membranes2017In: Application of Nanotechnology in Membranes for Water Treatment, CRC Press , 2017, p. 127-146Chapter in book (Other academic)
    Abstract [en]

    Heterogeneous photocatalysis based on oxide semiconductors is a promising technique for the prevention of microbial proliferation and to limit the growth of microorganisms. Among the studied photocatalysts, titanium dioxide (TiO2) represents one of the most interesting materials, due to its low cost, biocompatibility, chemical and thermal stability, and notable optical and dielectric properties. It exists in three polymorphic forms: rutile, which is the most stable form, anatase and brookite, both of which are metastable and convert into rutile upon heating. TiO2 nanoparticles can be efficiently obtained via different synthesis techniques, such as sol-gel, sol, hydrothermal, solvothermal, direct oxidation, chemical or physical vapor deposition, microwave, and reverse micelle methods, which offer the possibility to obtain well-controlled nanoparticle size and morphology. In the different TiO2 applications, its antimicrobial action has attracted a lot of attention in the last few decades. Particularly promising are the hybrid or mixed matrix TiO2- polymeric membranes, which allow separation and simultaneous photocatalytic reaction, without requiring any catalyst recovery operation. Several works have been published on the efficiency of the hybrid inorganic-organic membranes as antimicrobial systems, for bacteria, viruses, fungi and algae disruption. The TiO2 incorporation in/on the polymeric membrane also allows the reduction of fouling and at the same time highly improves water permeability and self-cleaning ability. 

  • 165. Martinez-Sanz, Marta
    et al.
    Olsson, Richard T.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Lopez-Rubio, Amparo
    Lagaron, Jose M.
    Development of electrospun EVOH fibres reinforced with bacterial cellulose nanowhiskers. Part I: Characterization and method optimization2011In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 18, no 2, p. 335-347Article in journal (Refereed)
    Abstract [en]

    In the present study, hybrid electrospun EVOH fibres reinforced with bacterial cellulose nanowhiskers (BCNW) were developed and characterized. The nanowhiskers, obtained by sulphuric acid digestion of native bacterial cellulose mats generated by Gluconacetobacter xylinum, were morphologically characterized by SEM and optical microscopy with polarized light and revealed a highly crystalline structure of nanofibrils aggregates. XRD analyses suggested a crystalline structure corresponding to the cellulose I allomorph. It was also confirmed by means of FT-IR spectroscopy that amorphous regions were preferentially digested by the acid treatment, whereas TGA analyses showed a decrease in the thermal stability of the nanowhiskers most likely due to incorporation of sulphate groups and the inherent acidity remaining in the filler even after extensive washing cycles. A method was developed for improving the incorporation of BCNW within the EVOH electrospun fibres, consisting on the addition of the BCNW in the form of a centrifuged precipitate, versus the most conventionally employed freeze-dried nanowhiskers. DSC analyses showed a significant increase in the glass transition temperature of the composites during the second heating run, which may be related to the acidic character of the nanofiller. Finally, sonication was seen to enhance interfacial interaction but to reduce the incorporation of the filler in the matrix in the case of the centrifuged material.

  • 166.
    Matsushita, Taishi
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Däcker, C. -Å
    Seetharaman, Seshadri
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Thermophysical properties of mould flux from Swedish steel companies2008In: Proc. ICS 2008: The 4th Int. Congress Sci. Technol. Steelmaking, 2008, p. 718-721Conference paper (Refereed)
  • 167.
    Mazinanian, Neda
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Metal Release and Corrosion of Stainless Steel in Simulated Food Contact2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Knowledge on metal release behaviour of stainless steels used in food processing applications and cooking utensils is essential within the framework of human health risk assessments. Recently, a new European test guideline (the CoE protocol) has been implemented to ensure safety of metals and alloys in food contact, such as stainless steels. This guideline suggests 5 gL-1 citric acid (pH 2.4) as a food simulant for acidic foods of pH ≤ 4.5. So far, limited assessments exist that investigate the correlation between the bioaccessibility, material characteristics, corrosion behaviour and surface chemistry of stainless steel for food application tests using citric acid. Therefore, this doctoral thesis comprises an in–depth interdisciplinary and multi–analytical research effort to fill this knowledge gap.

    This work includes thorough investigations of a range of stainless steel grades in simulated food contact as a function of different important parameters such as grades, surface finish, temperature, pH, solution composition, metal complexation and buffering capacity, concentration of the complex forming agents, loading, and repeated usage. This is accomplished by kinetic studies of metal release, electrochemical, and surface analytical investigations. Another focus of this thesis is to assess the dominating metal release process in citric acid or chloride containing solutions of varying pH.

    This study suggests protonation (at acidic pH) and surface complexation (at weakly acidic and neutral pH) as the predominant metal release mechanisms for stainless steel in citric acid solutions. Solution complexation may also play a role by hindering metal precipitation at weakly acidic and neutral pH, and metal release from surface defects / inclusions may initially be important for non-passivated surfaces.

  • 168.
    Mazinanian, Neda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Hedberg, Yolanda
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. Karolinska Institutet, Sweden.
    Metal Release Mechanisms for Passive Stainless Steel in Citric Acid at Weakly Acidic pH2016In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 163, no 10, p. C686-C693Article in journal (Refereed)
    Abstract [en]

    Metal release investigations from stainless steel into citric acid (CA) solutions at near-neutral pH are relevant for food applications, cleaning, and passivation. This study investigated metal release from abraded stainless steel grade AISI 304 into 5 g/L CA at pH 3.1, 4.8, and 6.4 at 40°C, as compared to a control solution (10 mM KNO3). Polyacrylic acid (PAA) was used as a model solution with and without separation from the stainless steel surface by a membrane. No significant difference was found for the released amounts of Fe and Mn between CA, PAA, and KNO3 solutions at pH 3.1, suggesting other mechanisms than complexation. At pH 4.8 and 6.4, a significantly higher release was found for CA and PAA solutions compared with KNO3 solution, but not for PAA solution when PAA molecules could not reach the stainless steel surface due to membrane separation, implying a dominant complexation-induced metal release mechanism that requires adsorption and/or close vicinity of the complexing agent to the surface. Cr was enriched in the surface oxide (surface passivation) in complexing solutions and the release of Cr was most dependent on complexation by CA at pH 4.8 and 6.4.

  • 169.
    Mazinanian, Neda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Hedberg, Yolanda
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Nickel release and surface characteristics of fine powders of nickel metal and nickel oxide in media of relevance for inhalation and dermal contact2013In: Regulatory toxicology and pharmacology, ISSN 0273-2300, E-ISSN 1096-0295, Vol. 65, no 1, p. 135-146Article in journal (Refereed)
    Abstract [en]

    Differences in surface oxide characteristics and extent of nickel release have been investigated in two thoroughly characterized micron-sized (mainly <4 mu m) nickel metal powders and a nickel oxide bulk powder when immersed in two different synthetic fluids, artificial sweat (ASW-pH 6.5) and artificial lysosomal fluid (ALF-pH 4.5) for time periods up to 24 h. The investigation shows significantly more nickel released from the nickel metal powders (<88%) compared to the NiO powder (<0.1%), attributed to differences in surface properties. Significantly more nickel was released from the nickel metal powder with a thin surface oxide predominantly composed of non-stoichiometric nickel oxide (probably Ni2O3), compared to the release from the nickel metal powder with a thicker surface oxide predominantly composed of NiO and to a lesser extent Ni2O3 (88% and 25% release after 24 h in ALF, respectively). Significantly lower amounts of nickel were released from the nickel metal powders in ASW (2.2% and <1%, respectively). The importance of particle and surface characteristics for any reliable risk assessment is discussed, and generated data compared with literature findings on bioaccessibility (released fraction) of nickel from powders of nickel metal and nickel oxide, and massive forms of nickel metal and nickel-containing alloys.

  • 170.
    Mazinanian, Neda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Herting, Gunilla
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Hedberg, Yolanda
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Metal release and corrosion resistance of different stainless steel grades in simulated food contact2016In: Corrosion, ISSN 0010-9312, E-ISSN 1938-159X, Vol. 72, no 6, p. 775-790Article in journal (Refereed)
    Abstract [en]

    A new technical guideline has been implemented by the Council of Europe (CoE) to ensure the stability and safety of food contact articles of metals and alloys, using 5 g/L citric acid (pH 2.4) and artificial tap water DIN 10531 (pH 7.5) as food simulants. The objectives of this study were: (i) to quantify the extent of metal release from austenitic (grades AISI 201, 204, 304, and 316L), ferritic (grades AISI 430 and EN 1.4003), and lean duplex stainless steel (grade EN 1.4162) in citric acid (5 g/L, pH 2.4) and in artificial tap water (pH 7.5); (ii) to compare the release of metals to the surface oxide composition, the open circuit potential-time dependence, and the corrosion resistance; and (iii) to elucidate the combined effect of high chloride concentrations (0.5 M NaCl) and citric acid at pH 2.2 and 5.5 on the extent of metal release from AISI 304 with and without prior surface passivation by citric acid. Exposures of all stainless steel grades in citric acid and artificial tap water up to 10 d (at 70°C/40°C) resulted in lower metal release levels than the specific release limits stipulated within the CoE protocol. For all grades, metals were released at levels close to the detection limits when exposed to artificial tap water, and higher release levels were observed when exposed to citric acid. Increased surface passivation, which resulted in reduced metal release rates with time, took place in citric acid for all grades and test conditions (e.g., repeated exposure at 100°C). There was no active corrosion in citric acid at pH 2.4. Fe (in citric acid) and Mn (in all solutions, but mostly tap water) were preferentially released, as compared to their bulk alloy content, from all stainless steel grades. Ni was released to the lowest extent. 0.5 M NaCl induced a very low (close to detection limits) metal release from grade AISI 304 at pH 5.5. When combined with citric acid (5 g/L) and at lower pH (2.2), 0.5 M NaCl induced slightly higher metal release compared to citric acid (pH 2.4) alone for coupons that were not pre-passivated. Pre-passivation in 5 g/L citric acid (pH 2.4) at 70°C for 2 h largely reduced this solution dependence. Pre-passivation resulted in an up to 27-fold reduced extent of metal release in solutions containing citric acid and/or NaCl at pH 2.2 to 5.5, and resulted in improved reproducibility among replicate samples.

  • 171.
    Mazinanian, Neda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Hedberg, Yolanda
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Influence of Citric Acid on the Metal Release of Stainless Steels2015In: Corrosion Science and Technology, ISSN 1598-6462, Vol. 14, no 4, p. 166-171Article in journal (Refereed)
    Abstract [en]

    Knowledge of how metal releases from the stainless steels used in food processing applications and cooking utensils is essential within the framework of human health risk assessment. A new European standard test protocol for testing metal release in food contact materials made from metals and alloys has recently been published by the Council of Europe. The major difference from earlier test protocols is the use of citric acid as the worst-case food simulant. The objectives of this study were to assess the effect of citric acid at acidic, neutral, and alkaline solution pH on the extent of metal release for stainless steel grades AISI 304 and 316, commonly used as food contact materials. Both grades released lower amounts of metals than the specific release limits when they were tested according to test guidelines. The released amounts of metals were assessed by means of graphite furnace atomic absorption spectroscopy, and changes in the outermost surface composition were determined using X-ray photoelectron spectroscopy. The results demonstrate that both the pH and the complexation capacity of the solutions affected the extent of metal release from stainless steel and are discussed from a mechanistic perspective. The outermost surface oxide was significantly enriched in chromium upon exposure to citric acid, indicating rapid passivation by the acid. This study elucidates the effect of several possible mechanisms, including complex ion- and ligand-induced metal release, that govern the process of metal release from stainless steel under passive conditions in solutions that contain citric acid.

  • 172.
    Midander, Klara
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Bioaccessibility of nano- and micron-sized metallic particles in simulated lung systems2008Conference paper (Refereed)
    Abstract [en]

    Ambient airborne particles of varying size and composition, originating from anthropogenic and natural sources are today a recognized health risk in the society. The rapid development of engineered nanomaterials, including particles, is believed to become an issue of large concern. At present, few efforts have been made to investigate potential adverse health effects of nano- and micron sized metallic particles. Reliable data on surface properties and reactivity of metallic particles and its correlation to toxicity is scarce. Bioaccessibility data, in terms of metal release, is believed to reflect the toxic effects of metallic particles. The metal release process is influenced by particle size, i.e. surface area, shape and material type, e.g. passive/non-passive, pure/alloy/oxide as well as the exposure environment, e.g. within the lung. The assessment of potentially adverse health effects due to particles requires the correlation between toxic effects, bioaccessibility properties and surface characteristics. Within this context, the material aspects of metal release from Cu-particles were studied in-vitro by exposure in different synthetic biological media that simulate, to some extent, a realistic inhalation scenario. Particle toxicity in terms of DNA damage and cytotoxic effects was studied in collaboration with human toxicologists at Karolinska Institutet, and aerosol scientists at Stockholm University, using epithelial human lung cells.

  • 173.
    Mikhaylova, Maria
    et al.
    KTH, Superseded Departments, Materials Science and Engineering.
    Kim, Do-Kyung
    KTH, Superseded Departments, Materials Science and Engineering.
    Berry, CC
    Zagorodni, Andrei
    KTH, Superseded Departments, Materials Science and Engineering.
    Toprak, Muhammet S.
    KTH, Superseded Departments, Materials Science and Engineering.
    Curtis, ASG
    Muhammed, Mamoun
    KTH, Superseded Departments, Materials Science and Engineering.
    BSA immobilization on amine-functionalized superparamagnetic iron oxide nanoparticles2004In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 16, no 12, p. 2344-2354Article in journal (Refereed)
    Abstract [en]

    Immobilization of bovine serum albumin (BSA) on surface-modified superparamagnetic iron oxide nanoparticles (SPION) has been performed by two different double-step immobilization approaches. The first approach consists of preparation of SPION by controlled chemical coprecipitation in the presence of BSA solution, whereas the second approach includes preliminary surface modification of SPION with an amine group using a coupling agent of 3-aminepropyltrimethoxysilane (APTMS). Both procedures are followed by 1-ethyl-3-(3-dimethylaminepropyl) carbodiimide hydrochloride (EDC) activation with sequential immobilization of the layer of BSA. Additionally, an attempt to modify the surface of SPION with amine and carboxylic groups is undertaken by using L-aspartic acid (LAA). TEM shows that the particle size varies in the range 10-15 nm and does not change significantly after the coating process. The presence of BSA and amine groups on the surface of SPION is confirmed by FT-IR. Magnetic properties are investigated by VSM and results indicate that the superparamagnetic properties are retained for BSA-coated SPION while reducing the value of saturation magnetization (M-s). The binding capacity is estimated from thermo-gravimetric and chemical analyse;. APTMS-coated SPION show higher BSA binding capacity compared to that of coprecipitated SPION in the presence of BSA. In vitro tests have been performed after the functionalization of SPION with LAA and BSA. Human dermal fibroblasts are incubated with the surface-modified SPION for 6 and 24 h to observe cell behavior, morphology, cytoskeletal organization, and interactions between cell and SPION. BSA-coated SPION incubated with cells demonstrated a cell response similar to that of control cells, with no adverse cell damage and no endocytosis, whereas LAA-coated SPION show partial endocytosis without cytoskeletal disorganization.

  • 174. Mille, C.
    et al.
    Tyrode, Eric C.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Corkery, Robert W.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry (closed 20110630).
    3-D chiral photonic crystals replicated from butterfly wing scales2011In: Materials Research Society Symposium Proceedings: Volume 1389, 2011, p. 7-12Conference paper (Refereed)
    Abstract [en]

    Three dimensional silica photonic crystals with the gyroid minimal surface structure have been synthesized using the butterfly Callophrys rubi as a template. The replicas are synthesized with a high degree of fidelity, which is confirmed by the spectral and morphological characterization. Further, the material is shown to be optically active.

  • 175. Mishra, G.
    et al.
    Mittal, Nitesh
    KTH, School of Engineering Sciences (SCI), Mechanics, Fluid Physics. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Sharma, A.
    Multifunctional Mesoporous Carbon Capsules and their Robust Coatings for Encapsulation of Actives: Antimicrobial and Anti-bioadhesion Functions2017In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 23, p. 19371-19379Article, review/survey (Refereed)
    Abstract [en]

    We present the synthesis and applications of multifunctional hollow porous carbon spheres with well-ordered pore architecture and ability to encapsulate functional nanoparticles. In the present work, the applications of hollow mesoporous carbon capsules (HMCCs) are illustrated in two different contexts. In the first approach, the hollow capsule core is used to encapsulate silver nanoparticles to impart antimicrobial characteristics. It is shown that silver-loaded HMCCs (concentration ?100 μg/mL) inhibit the growth and multiplication of bacterial colonies of Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) up to 96% and 83%, respectively. In the second part, the fabrication of hierarchical micro- and nanostructured superhydrophobic coatings of HMCCs (without encapsulation with silver nanoparticles) is evaluated for anti-bioadhesion properties. Studies of protein adsorption and microorganism and platelet adhesion have shown a significant reduction (up to 100%) for the HMCC-based superhydrophobic surfaces compared with the control surfaces. Therefore, this unique architecture of HMCCs and their coatings with the ability to encapsulate functional materials make them a promising candidate for a variety of applications.

  • 176. Mishra, Y. K.
    et al.
    Natarajan Arul, Murugan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Kotakoski, J.
    Adam, J.
    Progress in electronics and photonics with nanomaterials2017In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 146, p. 304-307Article in journal (Refereed)
    Abstract [en]

    Nanomaterials have been at the center of attraction for almost five decades as their contributions to different disciplines such as electronics, photonics and medicine are enormous. Various kinds of nanomaterials have been developed and are currently utilized in innumerable applications. Nevertheless, their simple realization and easy and efficient upscaling are topics under intense investigation. Innovative strategies have been adopted for nanomaterial synthesis and their usability. Here, we provide a brief overview on nanomaterials ranging from basic understanding of their structure-property relationship to advanced applications. This editorial covers various aspects about nanomaterials, which will be useful/attractive for beginners in the field of nanotechnology as well as for experts and for industrialists looking forward to exploit them for real world applications.

  • 177.
    Mittal, Nitesh
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Biotechnology (BIO), Protein Technology. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Jansson, Ronnie
    KTH, School of Biotechnology (BIO), Protein Technology.
    Widhe, Mona
    KTH, School of Biotechnology (BIO), Protein Technology.
    Benselfelt, Tobias
    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. Innventia AB, Sweden.
    Håkansson, Karl M. O.
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Lundell, Fredrik
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Biotechnology (BIO), Protein Technology. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Hedhammar, My
    KTH, School of Biotechnology (BIO), Protein Technology.
    Söderberg, Daniel
    KTH, School of Biotechnology (BIO), Protein Technology. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Ultrastrong and Bioactive Nanostructured Bio-Based Composites2017In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 11, no 5, p. 5148-5159Article in journal (Refereed)
    Abstract [en]

    Nature’s design of functional materials relies on smart combinations of simple components to achieve desired properties. Silk and cellulose are two clever examples from nature–spider silk being tough due to high extensibility, whereas cellulose possesses unparalleled strength and stiffness among natural materials. Unfortunately, silk proteins cannot be obtained in large quantities from spiders, and recombinant production processes are so far rather expensive. We have therefore combined small amounts of functionalized recombinant spider silk proteins with the most abundant structural component on Earth (cellulose nanofibrils (CNFs)) to fabricate isotropic as well as anisotropic hierarchical structures. Our approach for the fabrication of bio-based anisotropic fibers results in previously unreached but highly desirable mechanical performance with a stiffness of ∼55 GPa, strength at break of ∼1015 MPa, and toughness of ∼55 MJ m–3. We also show that addition of small amounts of silk fusion proteins to CNF results in materials with advanced biofunctionalities, which cannot be anticipated for the wood-based CNF alone. These findings suggest that bio-based materials provide abundant opportunities to design composites with high strength and functionalities and bring down our dependence on fossil-based resources.

  • 178. Molochnikov, L S
    et al.
    Kovalyova, E G
    Grigor'ev, I A
    Zagorodni, Andrei A.
    KTH, Superseded Departments, Materials Science and Engineering.
    Direct measurement of H+ activity inside cross-linked functional polymers using nitroxide spin probes2004In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 108, no 4, p. 1302-1313Article in journal (Refereed)
    Abstract [en]

    The lack of a direct method for measuring activity inside ion-exchamye resins was the main obstacle for strict thermodynamic investigations of such objects during the past decades. This paper proposes a method for the activity determination. The method is based on exploring the ESR response of stable nitroxide radicals introduced as probes into the resin phase. This method allows for the measurement of the hydrogen ion activity inside cross-linked polyelectrolytes. In addition to the method verification, the paper reports its application to the determination of ionization constants of functional groups and to the investigation of the hydrolysis and sorption of copper on different types of sorbents (weak cation and anion-exchange resins, functionalized and nonfunctionalized polymeric films). The applicability of known thermodynamic approaches developed for the investigation of micelles and biomembranes with nitroxide radicals is discussed. The paper also includes a critical analysis of the potentiometric method conventionally used for the investigation of ion-exchange equilibria.

  • 179.
    Mongkhontreerat, Surinthra
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Öberg, Kim
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Erixon, Lina
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Löwenhielm, Peter
    Hult, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Malkoch, Michael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    UV initiated thiol-ene chemistry: a facile and modular synthetic methodology for the construction of functional 3D networks with tunable properties2013In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 1, no 44, p. 13732-13737Article in journal (Refereed)
    Abstract [en]

    A facile methodology for the fabrication of functional crosslinked three dimensional (3D) networks has herein been explored via the benign and UV initiated thiol-ene coupling (TEC) chemistry. The careful selection of monomers or polymers and their feed ratio resulted in straightforward design of organic, inorganic and hydrogel networks with readily available alkenes or thiol functional groups. All crosslinked networks were fabricated within 1 second of UV exposure at wavelengths of 320-390 nm and generally exhibited excellent gel fractions around 90%. By introducing off-stoichiometric thiol and ene (OSTE) monomer feed ratios the window of mechanical properties could be manipulated. For the organic triazine system, the Young's modulus was altered from 780 MPa at an equimolar monomer ratio to soft 106 kPa for 2.5 equiv. with excess of thiol compared to enes. Postfunctionalizations with hydrophilic polyethylene glycols or acrylic acid and hydrophobic heneicosa-fluorododecyl acrylate were explored for the manipulation of functional networks. In this case, the rigid networks with excess of thiols were used as model substrates of which the initial contact angle (CA) of 60 degrees was decreased to 43 degrees by the introduction of acrylic acid and increased to 140 degrees by successful attachment of fluorinated molecules. Finally, amalgamating micropatterning strategy with simple postfunctionalizations of hydrophobic groups resulted in superhydrophobic rigid surfaces with a CA of 173 degrees.

  • 180. Moriana, Rosana
    et al.
    Vilaplana, Francisco
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Karlsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Ribes-Greus, Amparo
    Improved thermo-mechanical properties by the addition of natural fibres in starch-based sustainable biocomposites2011In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 42, no 1, p. 30-40Article in journal (Refereed)
    Abstract [en]

    Sustainable biocomposites based on thermoplastic starch copolymers (Mater-Bi KE03B1) and biofibres (cotton, hemp and kenaf) were prepared and characterised in terms of their thermo-mechanical and morphological properties. Biocomposites exhibit improved thermal stability and mechanical properties in comparison with the Mater-Bi KE. Biofibres act as suitable thermal stabilizers for the Mater-Bi KE, by increasing the maximum decomposition temperature and the Ea associated to the thermal decomposition process. Biofibre addition into the Mater-Bi KE results in higher storage modulus and in a reduction of the free-volume-parameter associated to the Mater-Bi KE glass transition. The influence of different biofibres on the thermo-mechanical properties of the biocomposites has been discussed. Hemp and kenaf enhance the thermal stability and reduce the free volume-parameter of Mater-Bi KE more significantly than cotton fibres, although the latter exhibits the highest mechanical performance. These differences may be explained by the improved interaction of lignocellulosic fibres with the Mater-Bi KE, due to the presence of hemicellulose and lignin in their formulation.

  • 181. Muhmood, L.
    et al.
    Viswanathan, N. N.
    Seetharaman, Seshadri
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Process Science.
    A new approach for the diffusion coefficient evaluation of sulfur in CaO-SiO2-Al2O3 slag2011In: 6th International Conference on Diffusion in Solids and Liquids, DSL-2010, 2011, p. 626-634Conference paper (Refereed)
    Abstract [en]

    The Diffusion coefficient of sulfur in a ternary slag with composition of 51.5% CaO- 9.6% SiO2- 38.9% Al2O3 was measured at 1723 K by chemical diffusion from the variation of concentration of sulfur in silver metal. A MATLAB program was developed to find the concentration variation of sulfur in silver metal using various critical parameters like the diffusion coefficient of sulfur in slag available in literature, sulfur partition ratio, sulfide capacity of the slag and the its density. The P S2 and PO2 pressures were calculated from the Gibbs energy of the equilibrium reaction between CaO in the slag and solid CaS and confirming the same by using ThermoCalc. The density of the slag at 1723 K was obtained from earlier experiments. Initially the order of magnitude for the diffusion coefficient was taken from the works of Saito and Kawai but later was modified so that the concentration changes of Sulfur obtained from the program agreed with the experimental results. The diffusion coefficient of sulfur in 51.5% CaO- 9.6% SiO2- 38.9% Al2O3 slag at 1723 K was estimated as 4.14×10-6 cm2/sec.

  • 182. Naderi, Ali
    et al.
    Lindstrom, Tom
    Weise, Christoph F.
    Flodberg, Goren
    Sundstrom, Jonas
    Junel, Kristina
    Erlandsson, Johan
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Runebjork, AnneMarie
    Phosphorylated nanofibrillated cellulose: production and properties2016In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 1, p. 20-29Article in journal (Refereed)
    Abstract [en]

    Phosphate functionalized nanofibrillated cellulose (NFC) was produced through an industrially attractive process, by reacting wood pulp with a phosphate containing salt, followed by mechanical delamination through microfluidization. The degrees of delamination of the phosphorylated NFCs (judged by among others AFM-imaging, rheological studies and tensile strength measurements on NFC films) were found to improve with increasing functionalization of the pulp and number of microfluidization-passes. The NFC systems were found to display similar characteristics as other well-known NFC systems. Interestingly, however, the sufficiently delaminated phosphorylated NFCs exhibited significantly lower oxygen permeability values (at RH 50%) than the published values of several well-known highly delaminated NFC systems. The potential application of the phosphorylated NFC in packaging applications can hence be envisaged.

  • 183.
    Neranon, Kitjanit
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Stimuli-Responsive, Multivalent Glycodendrimer/Metalloglycodendrimer Assemblies for Targeted DeliveryManuscript (preprint) (Other academic)
  • 184.
    Nordenström, Malin
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Riazanova, Anastasia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Järn, Mikael
    RISE Res Inst Sweden, Div Biosci & Mat, SE-11428 Stockholm, Sweden..
    Paulraj, Thomas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Turner, Charlotta
    Lund Univ, Dept Chem, SE-22100 Lund, Sweden..
    Ström, Valter
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Olsson, Richard
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Svagan, Anna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Superamphiphobic coatings based on liquid-core microcapsules with engineered capsule walls and functionality2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 3647Article in journal (Refereed)
    Abstract [en]

    Microcapsules with specific functional properties, related to the capsule wall and core, are highly desired in a number of applications. In this study, hybrid cellulose microcapsules (1.2 +/- 0.4 mu m in diameter) were prepared by nanoengineering the outer walls of precursor capsules. Depending on the preparation route, capsules with different surface roughness (raspberry or broccoli-like), and thereby different wetting properties, could be obtained. The tunable surface roughness was achieved as a result of the chemical and structural properties of the outer wall of a precursor capsule, which combined with a new processing route allowed in-situ formation of silica nanoparticles (30-40 nm or 70 nm in diameter). By coating glass slides with "broccoli-like" microcapsules (30-40 nm silica nanoparticles), static contact angles above 150 degrees and roll-off angles below 6 degrees were obtained for both water and low surface-tension oil (hexadecane), rendering the substrate superamphiphobic. As a comparison, coatings from raspberry-like capsules were only strongly oleophobic and hydrophobic. The liquid-core of the capsules opens great opportunities to incorporate different functionalities and here hydrophobic superparamagnetic nanoparticles (SPIONs) were encapsulated. As a result, magnetic broccoli-like microcapsules formed an excellent superamphiphobic coating-layer on a curved geometry by simply applying an external magnetic field.

  • 185.
    Norlin, Anna
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Fabrication of Porous Nb2O5 by Plasma Electrolysis Anodization and Electrochemical Characterization of the Oxide2006In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 153, no 7, p. B225-B230Article in journal (Refereed)
    Abstract [en]

    Porous Nb2O5 electrodes were fabricated by applying anodic pulses of 700 V and 10 ms duration to pure Nb in phosphate bufferedsaline solution (PBS), aiming at biomaterial applications. The porosity of the oxide could be controlled by the number of pulses. X-ray photoelectron spectroscopy analysis confirmed the oxide to be Nb2O5. The electrochemical behavior and interfacial propertiesof the porous Nb2O5 were characterized in PBS by using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). EIS measurements indicate that the oxide film has a two-layer structure with a compact inner layer and a porousouter layer, and the pores were sealed by precipitates during long-time aging in PBS. The two-layer structure of the oxide film wasobserved by examination of the cross section using scanning electron microscopy in backscatter mode. The CV measurementsreveal that the oxide exhibits an electrochemical “rectifying” property. It is stable over a wide potential range but shows hydrogenuptake upon cathodic polarization below −1 V vs Ag/AgCl.

  • 186.
    Noroozi, Mohammad
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Abedin, Ahmad
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Moeen, Mahdi
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Radamson, Henry H.
    CVD growth of GeSnSiC alloys using disilane, digermane, tin tetrachloride and methylsilane2014In: ECS Transactions, 2014, Vol. 64, no 6, p. 703-710Conference paper (Refereed)
    Abstract [en]

    In this study, Ge1-x-y-zSnxSiyCz layers (0.01≤x≤ 0.06, 0≤y≤0.02 and 0≤z≤0.01) have been successfully grown at 280-330 °C on Ge and Si by using RPCVD technique. It was demonstrated that the quality of epitaxial layers is dependent on the growth parameters, layer thickness and the quality of Ge virtual layer. It was found that a proper strain balance in the matrix during the epitaxy where the Si is adjusted carefully with the Sn flux improves the incorporation of Sn in Ge matrix. A similar improvement of Sn incorporation has been observed for phosphorous, boron and carbon doping in GeSn layers as well. This is explained by the compensation of the compressive strain caused by Snand the tensile strain induced by Si to obtain the minimum energy in Ge matrix. This behavior was not observed for relaxed GeSn layers and Sn incorporation could be controlled only by the growth parameters. The thermal stability of GeSn is an important integration issue for device fabrication. The thermal stability of P- and B-doped GeSn layers was studied by rapid thermal annealing (RTA) in range of 400-600 °C and compared with intrinsic layers. The GeSn layers were stable up to 550 °C while the B-doped layers showed strain relaxation readily at 500 °C. The epitaxial quality of epi-layers was evaluated in terms of oxygen and water vapor contamination. The level of oxygen during epitaxy was as low as 10 ppb and the contamination amount was found as low as 1017 cm-3.

  • 187.
    Nowak, Andrzej
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Hagberg, Johan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Leijonmarck, Simon
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Schweinebarth, Hannah
    Baker, Darren
    Uhlin, Anders
    Tomani, Per
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Lignin-based carbon fibers for renewable and multifunctional lithium-ion battery electrodes2018In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 72, no 2, p. 81-90Article in journal (Refereed)
    Abstract [en]

    Lignin-based carbon fibers (LCFs) from the renewable resource softwood kraft lignin were synthesized via oxidative thermostabilization of pure melt-spun lignin and carbonization at different temperatures from 1000 degrees C to 1700 degrees C. The resulting LCFs were characterized by tensile testing, scanning electron microscopy (SEM), X-ray diffraction (XRD) and confocal Raman spectroscopy. The microstructure is mainly amorphous carbon with some nanocrystalline domains. The strength and stiffness are inversely proportional to the carbonization temperature, while the LCFs carbonized at 1000 degrees C exhibit a strength of 628 MPa and a stiffness of 37 GPa. Furthermore, the application potential of LCFs was evaluated as negative electrodes in a lithium-ion battery (LIB) by electrochemical cycling at different current rates in a half-cell setup. The capacity drops with the carbonization temperature and the LCFs carbonized at 1000 degrees C have a capacity of 335 mAh g(-1). All LCFs showed good cycling stability. Because of the mechanical integrity and conductivity of the LCFs, there is no need to apply current collectors, conductive additives or binders. The advantage is an increased gravimetric energy density compared to graphite, which is the most common negative electrode material. LCFs show a promising multifunctional behavior, including good mechanical integrity, conductivity and an ability to intercalate lithium for LIBs.

  • 188. Ohm, Wiebke
    et al.
    Rothkirch, Andre
    Pandit, Pallavi
    Koerstgens, Volker
    Mueller-Buschbaum, Peter
    Rojas, Ramiro
    Yu, Shun
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Brett, Calvin J.
    Soderberg, Daniel L.
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Morphological properties of airbrush spray-deposited enzymatic cellulose thin films2018In: JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, ISSN 1945-9645, Vol. 15, no 4, p. 759-769Article in journal (Refereed)
    Abstract [en]

    We investigate the layer formation of enzymatic cellulose by airbrush spray coating on silicon oxide surfaces. The layer structure and morphology of enzymatic cellulose films in the thickness range between 86 nm and 2.1 A mu m is determined as a function of the spray coating procedures. For each spray coating step, layer buildup, surface topography, crystallinity as well as the nanoscale structure are probed with atomic force microscopy and surface-sensitive X-ray scattering methods. Without intermittent drying, the film thickness saturates; with intermittent drying, a linear increase in layer thickness with the number of spray pulses is observed. A closed cellulose layer was always observed. The crystallinity remains unchanged; the nanoscale structures show three distinct sizes. Our results indicate that the smallest building blocks increasingly contribute to the morphology inside the cellulose network for thicker films, showing the importance of tailoring the cellulose nanofibrils. For a layer-by-layer coating, intermittent drying is mandatory.

  • 189.
    Olin, Pontus
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Fundamentals of Wetting and Mechanical Durability of Superhydrophobic Coatings2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In paper I the friction between three different superhydrophobic surfaces and water drops were investigated using high‑speed video. The surfaces were two based on a hydrophobic wax and the third was the leaf of a Lotus (Nelumbo Nucifera). The acceleration of water drops was measured as a function of drop size and surface inclination. For small capillary numbers it was shown that the dissipation was dominated by pinning‑depinning transitions along the trailing contact line. A parameter called the superhydrophobic sliding resistance bsh has been introduced. The motion of drops on superhydrophobic surfaces of a general macroscopic topography can be predicted provided that bsh and the drop size are known. This theory also infers the existence of an equilibrium sliding angle, beq, at which the drop acceleration is zero.

    The effect of line‑shaped defects on the motion of water drops on superhydrophobic surfaces were also investigated using high‑speed video in paper II. It was shown that the motion of the drop in the vicinity of the defect can be approximated by a damped harmonic oscillator. Whether a drop got trapped or not while traversing the defect was determined by the incident speed and the characteristics of the oscillator. In systems with low viscous dissipation it is possible to predict the trapping speed as well as the exit speed using a simple work‑energy consideration.

    The resistance of wax based superhydrophobic coatings subjected to different types of mechanical damage were investigated in paper III. Scratch tests were performed using atomic force microscopy (AFM) and rubbing with an index finger. Coatings were also subjected to compression with a silicone rubber stamp. The effect of impacting water drops was also investigated. A load of 12 nN was enough to remove the coating from the substrate. The coatings remained superhydrophobic at compression pressures up to 59 kPa but the superhydrophobic properties were lost after only one stroke with a finger. The coatings resisted at least 200 000 impacts of falling water drops without losing their superhydrophobic properties.

    In paper IV superhydrophobic coatings were fabricated in a semi‑continuous process, where an alkyl ketene dimer (AKD) was dissolved in supercritical carbon dioxide (scCO2) and sprayed onto the substrate. Several different substrates such as: glass, aluminium, paper, poly (ethylene terephthalate) (PET) and poly (tetrafluoroethylene) (PTFE) were successfully coated. The most efficient spray process, considering surface properties and mass of extracted AKD, was obtained at the lowest temperature investigated, 67 °C, and the highest pressure evaluated in this study, 25 MPa. The influence of the pre‑expansion conditions (p, T) on the surface temperature (at a spray distance of 3 cm) was also shown to be negligible.

  • 190.
    Olin, Pontus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Lindström, Stefan B.
    Solid Mechanics , Department of Management and Engineering, the Institute of Technology, Linköping University.
    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.
    Trapping of Water Drops by Defects on Superhydrophobic SurfacesManuscript (preprint) (Other academic)
    Abstract [en]

    In this work the effect of line‑shaped defects on the motion of water drops on superhydrophobic surfaces have been investigated using high‑speed video. The defects were introduced on superhydrophobic wax surfaces by a simple scratching method. It is shown that the motion of the drop in the vicinity of the defect can be approximated by a damped harmonic oscillator. Whether a drop gets trapped or not while traversing the defect is determined by the incident speed and the characteristics of the oscillator, more specifically by the damping ratio z and the nondimensional forcing constant â. We also show that it is possible to predict the trapping speed as well as the exit speed using a simple work‑energy consideration in systems with negligible viscous dissipation.

  • 191.
    Olupot, Peter Wilberforce
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Mechanical Metallurgy.
    Jonsson, Stefan
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Mechanical Metallurgy.
    Byaruhanga, Joseph K.
    Characterization of feldspar and quartz raw materials in Uganda for manufacture of electrical porcelains2006In: Journal of the Australasian Ceramic Society, ISSN 1018-6689, Vol. 42, no 1, p. 29-35Article in journal (Refereed)
    Abstract [en]

    Electric porcelains are widely used for insulation purposes. The aim of this study is to characterize feldspar and quartz raw materials in Uganda for use in manufacture of electric porcelains. Samples from two deposits of each feldspar and silica are investigated to assess their potential as raw materials in the manufacture of electric porcelains. Raw samples ground to powder form are investigated by means of X-ray diffraction, thermal analysis, and scanning electron microscopy. In addition, the chemical composition, particle size distribution and density of the powders are determined. The study reveals one of the feldspar deposits to consist of purely ordered microcline, while the other has ordered microcline, quartz and albite. The silica deposits are purely of quartz mineral. The materials investigated, are suitable for use in porcelain production.

  • 192.
    Ovaskainen, Louise
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Olin, Pontus
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Tuominen, Mikko
    SP Kemi, Material och Ytor, Drottning Kristinas väg 45, SE-114 86 Stockholm.
    Pettersson, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    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.
    Wear studies of superhydrophobic coatings of wax sprayed from rapid expansion of supercritical solutions (RESS)Manuscript (preprint) (Other academic)
    Abstract [en]

    The wear resistance of superhydrophobic coatings made by spraying a wax from supercritical carbon dioxide solutions have been evaluated by different methods. Scratch tests were performed by using the tip of the cantilever in an atomic force microscope (AFM) by applying an increasing load force on the tip during the measurement. Compression tests were also performed by applying different loads onto a rubber stamp that was placed on the surfaces. In addition to this, frictional wear was evaluated by moving an index finger over the surface using a device that measured the applied load and frictional forces. The wetting properties of the exposed coatings were subsequently evaluated in terms of advancing and receding water contact angles, the superhydrophobic sliding resistance parameter and the surface roughness (RMS). The morphology of the coatings was studied by scanning electron microscopy and optical profilometry. Scratching, with the AFM, at load forces of 12 nN was enough to fully remove the coating from the underlying silica substrate. Results also show that the surfaces remained superhydrophobic after being exposed to compression loads up to 59 kPa. The frictional wear measurments showed that the superhydrophobic properties were immediately lost after pressing and moving a finger over the coating since the lateral movement destroyed the fine surface structure.  Finally it was found that the surfaces could stand up to 200 000 falling water drops without losing its superhydrophobicity.

  • 193.
    Pan, Shiwei
    et al.
    Univ Sci & Technol Beijing, State Key Lab Adv Met & Mat, Beijing 100083, Peoples R China..
    Zhou, Xianglin
    Univ Sci & Technol Beijing, State Key Lab Adv Met & Mat, Beijing 100083, Peoples R China..
    Chen, Kaixuan
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Univ Sci & Technol Beijing, Inst Adv Mat & Technol, Beijing 100083, Peoples R China.
    Yang, Ming
    Univ Sci & Technol Beijing, Sch Mat Sci & Engn, Beijing 100083, Peoples R China..
    Cao, Yudong
    Univ Sci & Technol Beijing, Inst Adv Mat & Technol, Beijing 100083, Peoples R China..
    Chen, Xiaohua
    Univ Sci & Technol Beijing, State Key Lab Adv Met & Mat, Beijing 100083, Peoples R China..
    Wang, Zidong
    Univ Sci & Technol Beijing, Sch Mat Sci & Engn, Beijing 100083, Peoples R China..
    In-Situ Nanoparticles: A New Strengthening Method for Metallic Structural Material2018In: Applied Sciences, E-ISSN 2076-3417, Vol. 8, no 12, article id 2479Article, review/survey (Refereed)
    Abstract [en]

    Over the past several years, coherent interface strengthening was proposed and has since drawn much attention. Unfortunately, many fabrication techniques are restricted to very small size. Recently, a brand new method of in-situ nanoparticle strengthening was systematically investigated, which was proved to be an efficacious way to optimize microstructure and improve mechanical property by utilizing uniformly dispersed nanoparticles. In this review, we summarized recent related advances in investigated steels and Cu alloys, including details of preparation technique and characterization of in-situ nanoparticles. In-situ nanoparticles formed in the melt possess a coherent/semi-coherent relationship with the matrix, which has a similar effect of coherent interface strengthening. In this case, bulk metallic structural materials with dispersed nanoparticles in the matrix can be fabricated through conventional casting process. The effects of in-situ nanoparticles on grain refinement, inhibiting segregation, optimizing inclusions and strengthening are also deeply discussed, which is beneficial for obtaining comprehensive mechanical response. Consequently, it is expected that in-situ nanoparticle strengthening method will become a potential future direction in industrial mass production.

  • 194. Pasti, Igor A.
    et al.
    Leetmaa, Mikael
    Skorodumova, Natalia V.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Uppsala Univiversity, Sweden.
    General principles for designing supported catalysts for hydrogen evolution reaction based on conceptual Kinetic Monte Carlo modeling2016In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 41, no 4, p. 2526-2538Article in journal (Refereed)
    Abstract [en]

    Rational catalyst design presents one of the main paradigms in the contemporary materials science. Although the electronic structure calculations can be used to search for possible candidates, realistic supported catalysts are difficult to address in this way. In this contribution we use conceptual model of the supported hydrogen evolution reaction (HER) catalyst and investigate possible processes using Kinetic Monte Carlo simulations. In specific, we look at the possibility to boost H-2 production by the H spillover to the support and the tailoring of the catalyst deposit. Different scenarios were considered depending on the nature of the HER rate determining step (RDS) on the catalyst surface and the effects of the rates of elementary processes, catalyst dispersion and morphology are analyzed. Metals with low affinity towards hydrogen should be used as catalyst supports, while H spillover can boost H-2 production if Tafel or Heyrovsky reaction is the RDS on the catalyst surface. However, this can be achieved only if the catalyst dispersion is high, while the support has to act as a Hads acceptor and enable fast Hads recombination. General instructions for the choice of the catalystlsupport combination can be used to design new advanced HER catalysts. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  • 195.
    Paulraj, Alagar R.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Kiros, Yohannes
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Skårman, B.
    Höganäs AB, SE-26383 Höganäs, Sweden.
    Vidarsson, H.
    Höganäs AB, SE-26383 Höganäs, Sweden.
    Core/shell structure nano-iron/iron carbide electrodes for rechargeable alkaline iron batteries2017In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 164, no 7, p. A1665-A1672Article in journal (Refereed)
    Abstract [en]

    In this work, we have studied a 2% copper substituted core shell type iron/iron carbide as a negative electrode for application in energy storage. The NanoFe-Fe3C-Cu delivered 367 mAh g−1 at ≈80% current efficiency, successfully running for over 300 cycles. The superior electrode kinetics and performance were assessed by rate capability, galvanostatic, potentiodynamic polarization measurements in 6 M KOH electrolyte and at ambient temperature. Ex-situ XRD characterizations and SEM images of both the fresh and used electrode surfaces show that nanoparticles were found to be still intact with negligible particle agglomeration. The electrodes have shown stable performances with low capacity decay, whereas sulfur dissolution from the additive Bi2S3 was found to decrease the charging efficiency with time. This core-shell type structured nano material is, consequently, an auspicious anode candidate in alkaline-metal/air and Ni-Fe battery systems.

  • 196. Pena, Alexandra
    et al.
    Menaert, Bertrand
    Debray, Jerome
    Canalias, Carlota
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics. KTH, School of Engineering Sciences (SCI), Physics.
    Boulanger, Benoit
    Stability of the polar faces in KTiOPO4 crystalline layers grown by liquid phase epitaxy2018In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 20, no 46, p. 7502-7506Article in journal (Refereed)
    Abstract [en]

    The polar faces, (001) and (001), of the ferroelectric KTiOPO4 crystal are not equivalent by symmetry. The stability and the growth rate of both faces have been determined by growing thick crystalline layers by liquid phase epitaxy onto oriented crystalline commercial KTiOPO4 slabs. Growth solutions with different molar compositions in the system KTiOPO4-KPO3-KF and different supersaturation degrees end up with the same result. Whereas the (00 (1) over bar) faces are stable under all the experimental conditions used, the (001) ones are not stable and turn into (00 (1) over bar) faces. Head-to-head domains oriented along the [010] axis at vertical bar 7 +/- 1 degrees vertical bar to the [001] axis propagate from the (001) surface of the seed to the as-grown crystalline layers. The final epitaxies obtained by this process show two (00 (1) over bar) polar end faces; so a twin-crystal along the c direction was grown.

  • 197.
    Petronico, Aaron
    et al.
    Univ Illinois, Dept Chem, Urbana, IL 61801 USA..
    Moneypenny, Timothy P., II
    Univ Illinois, Dept Chem, Urbana, IL 61801 USA.;Univ Illinois, Beckman Inst Adv Sci & Technol, Urbana, IL 61801 USA..
    Nicolau, Bruno G.
    Univ Illinois, Dept Chem, Urbana, IL 61801 USA..
    Moore, Jeffrey S.
    Univ Illinois, Dept Chem, Urbana, IL 61801 USA.;Univ Illinois, Beckman Inst Adv Sci & Technol, Urbana, IL 61801 USA..
    Nuzzo, Ralph G.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Univ Illinois, Dept Chem, Urbana, IL 61801 USA.
    Gewirth, Andrew A.
    Univ Illinois, Dept Chem, Urbana, IL 61801 USA..
    Solid-Liquid Lithium Electrolyte Nanocomposites Derived from Porous Molecular Cages2018In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 140, no 24, p. 7504-7509Article in journal (Refereed)
    Abstract [en]

    We demonstrate that solid-liquid nanocomposites derived from porous organic cages are effective lithium ion electrolytes at room temperature. A solid-liquid electrolyte nanocomposite (SLEN) fabricated from a LiTFSI/DME electrolyte system and a porous organic cage exhibits ionic conductivity on the order of 1 x 10(-3) S cm(-1). With an experimentally measured activation barrier of 0.16 eV, this composite is characterized as a superionic conductor. Furthermore, the SLEN displays excellent oxidative stability up to 4.7 V vs Li/Li+. This simple three-component system enables the rational design of electrolytes from tunable discrete molecular architectures.

  • 198.
    Pettersson, Torbjörn
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Pendergraph, Samuel A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Utsel, Simon
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Marais, Andrew
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Gustafsson, Emil
    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.
    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.
    Robust and Tailored Wet Adhesion in Biopolymer Thin Films2014In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 15, no 12, p. 4420-4428Article in journal (Refereed)
    Abstract [en]

    Model layer-by-layer (LbL) assemblies of poly(allylamine hydrochloride) (PAH) and hyaluronic acid (HA) were fabricated in order to study their wet adhesive behavior. The film characteristics were investigated to understand the inherent structures during the assembly process. Subsequently, the adhesion of these systems was evaluated to understand the correlation between the structure of the film and the energy required to separate these LbL assemblies. We describe how the conditions of the LbL fabrication can be utilized to control the adhesion between films. The characteristics of the film formation are examined in the absence and presence of salt during the film formation. The dependence on contact time and LbL film thickness on the critical pull-off force and work of adhesion are discussed. Specifically, by introducing sodium chloride (NaCl) in the assembly process, the pull-off forces can be increased by a factor of 10 and the work of adhesion by 2 orders of magnitude. Adjusting both the contact time and the film thickness enables control of the adhesive properties within these limits. Based on these results, we discuss how the fabrication procedure can create tailored adhesive interfaces with properties surpassing analogous systems found in nature.

  • 199. Piskounova, Sonya
    et al.
    Rojas, Ramiro
    Bergman, Kristoffer
    Hilborn, Jöns
    The Effect of Mixing on the Mechanical Properties of Hyaluronan-Based Injectable Hydrogels2011In: Macromolecular Materials and Engineering, ISSN 1438-7492, Vol. 296, no 10, p. 944-951Article in journal (Refereed)
    Abstract [en]

    A method for determining the correlation between the mixing of two reactive polymers and the structural and mechanical properties of the formed hydrogels is presented. Rheological measurements show that insufficient mixing gives rise to soft and not fully crosslinked hydrogels while excessive mixing beyond gel point results in weaker hydrogels due to potential breakage of their 3D network. Furthermore, the hydrogels swell significantly more in cell culture medium than in phosphate-buffered saline, attributed to interactions with additional molecules such as proteins. Thus, moderate mixing gives rise to the most homogenous and mechanically stable hydrogels and the choice of medium e. g., for release experiments, should be consistent in order to avoid unnecessary variations in the data caused by different swelling profiles.

  • 200. Pu, Tingting
    et al.
    Tan, Wenyi
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Nanjing Institute of Technology, Nanjing, China.
    Shi, Huangang
    Na, Yi
    Lu, Jiangang
    Zhu, Bin
    Steam/CO2 electrolysis in symmetric solid oxide electrolysis cell with barium cerate-carbonate composite electrolyte2016In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 190, p. 193-198Article in journal (Refereed)
    Abstract [en]

    A composite electrolyte, Zr doped BaCe0.8Y0.2O3-delta (BaCe0.8Y0.2O3-delta, BCZY) and binary carbonates [(Li,Na)(2)CO3] (LNCO) was first applied to reduce CO2 accompanied with steam electrolysis in solid oxide electrolysis cell (SOEC) at 600 degrees C, lower than which conventional SOEC composed by YSZ works in (usually above 800 degrees C). Electrolysis performances are improved due to sufficient steam feed at oxygen electrode side (30-110 ml/min). Steam electrolysis provides proton source for the reduction of CO2. Application of composite electrolyte promotes proton transport and directly leads to H-2 even CH4 production. To a certain degree, carbon resistance guarantees the symmetric SOEC operation at a lower bias potential of 0.5 V (vs.00V) applied. A redox-stable and carbon-tolerant LSCM as symmetric electrode with a hybrid-ion-conducting composite electrolyte realizes the fuel synthesis by CO2 reduction in proton-type solid oxide electrolyzer.

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