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  • 301.
    Jain, Sagar Motilal
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry. Univ Turin, NIS Nanostruct Interfaces & Surfaces Ctr Excellen, Dept Chem, Via P Giuria 7, I-10125 Turin, Italy.; Swansea Univ, Coll Engn, Bay Campus,Fabian Way, Swansea SA1 8EN, W Glam, Wales.
    Tripathi, Sapana
    Max Planck Inst Intelligent Syst, Dept Magnet Mat, Heisenbergstr 3, D-70569 Stuttgart, Germany.
    Tripathi, Sanjay
    Mahakal Inst Technol & Management, Dept Mech Engn, Dewas Rd, Ujjain 456664, MP, India.
    Spoto, Giuseppe
    Univ Turin, NIS Nanostruct Interfaces & Surfaces Ctr Excellen, Dept Chem, Via P Giuria 7, I-10125 Turin, Italy.
    Edvinsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Acid-catalyzed oligomerization via activated proton transfer to aromatic and unsaturated monomers in Nafion membranes: a step forward in the in situ synthesis of conjugated composite membranes2016In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 6, no 106, p. 104782-104792Article in journal (Refereed)
    Abstract [en]

    An approach to perform controlled acid-catalyzed oligomerization via vapor pressure control of thereactions inside Nafion membranes is presented. The interaction of Nafion with several classes ofaromatic (pyrrol, furan, thiophene) and unsaturated (methyl-acetylene) gas phase monomers was studiedas a function of contact time and temperature by in situ vibrational (FTIR) and electronic (UV-Vis)spectroscopy with the support from theoretical linear response and time dependent DFT calculations tomonitor the vibrations and the effective number of conjugated double bonds. The formation ofH-bonded adduct as seen from IR spectroscopy transforms the hydrogen bonded species into positivelycharged oligomers through an activated proton transfer mechanism where oligomerization progressthrough increasing contact time with the respective gas phase reactants at room temperature. Theactivated proton transfer oligomerization proceeds through the stepwise growth propagation cycles viacarbocationic intermediates, finally leads to the formation of irreversible, conjugated charged oligomersas a product. The colored, conjugated oligomeric Nafion composite products are formed at roomtemperature as a function of reaction time and are irreversible after complete degassing of the gas phasereactants as well stable in ambient environment stored for many days in pure oxygen or air and cannotbe extracted with common solvents, appearing strongly encapsulated inside Nafion membranes. This iscrucial for future applications of the presented route for direct production of conjugated species insideNafion and thus production and control of composite membrane materials of interest in fuel cells andcatalysis.

  • 302. Jakli, Antal
    et al.
    Taushanoff, Stefanie
    Molnar, Matyas
    Bota, Attila
    Kalman, Erika
    Varga, Zoltan
    Palinkas, Peter
    Palinkas, Andrea
    Method for preparing anisotropic particles and devices thereof2010Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    The invention provides a simple and cost-effective method for preparing particles such as anisotropic semiconductor nanoparticles (e.g. CdS) and devices thereof. The method comprises (i) dispersing at least part of particle-forming reactants in a self-organized medium such as surfactant-aqueous solution system, and (ii) conducting a particle-forming reaction using the particle-forming reactants dispersed in the self-organized medium under shear condition to form the particles. The anisotropic property of the particles is controlled at least partially by the shear condition. The invention may be used to prepare quantum dots in a liquid crystal, and various devices such as nonlinear optics, optoelectronic devices, and solar cells, among others.

  • 303. Janer, G
    et al.
    Park, M
    Catalán, J
    Ferraz, Natalia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Cabellos, J
    Vanhauten, R
    Challenges and lessons learnt during the implementation into the GUIDEnano Tool of a systematic evaluation of similarity between nanomaterials.2017Conference paper (Refereed)
  • 304.
    Janson, Oscar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Welch, Ken
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Effect of irradiated TiO2/H2O2 suspensions on Staphylococcus epidermidis biofilm2017In: 10th annual meeting for Scandinavian Society for Biomaterials (ScSB) 2017: Underlying Challenges in Biomaterials, 2017, article id 15Conference paper (Refereed)
  • 305.
    Janson, Oscar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Welch, Ken
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Debridement of Bacterial Biofilms with TiO2/H2O2 Solutions and Visible Light Irradiation2018In: International Journal of Biomaterials, ISSN 1687-8787, E-ISSN 1687-8795, Vol. 2018, article id 5361632Article in journal (Refereed)
    Abstract [en]

    Objectives. The aim of the study was to explore the debridement efficacy of different solutions of H2O2 and rutile particles against Staphylococcus epidermidis and Pseudomonas aeruginosa biofilms attached to titanium surfaces when exposed to visible light. Materials and Methods. Titanium discs cultivated with biofilms of Staphylococcus epidermidis or Pseudomonas aeruginosa were subjected for 1 min to suspensions consisting of rutile particles mixed with high (950 mM) or low (2 mM) concentrations of H2O2 under visible light irradiation (405 nm; 2.1 mW/cm2). Discs were rinsed and the degree of debridement was determined through scanning electron microscopy and viability assessment of the remaining bacteria using luminescence measurements and/or a metabolic activity assay. Results. Cleaning mixtures containing the higher concentration of H2O2 showed a significantly improved debridement compared to the negative control in all experiments. The addition of rutile particles was shown to have a statistically significant effect in one test with S. epidermidis. Limited evidence of the catalytic effect of visible light irradiation was seen, but effects were relatively small and statistically insignificant. Conclusions. H2O2 at a concentration of 950 mM proved to be the strongest contribution to the debridement and bactericidal effect of the cleaning techniques tested in this study.

  • 306.
    Janson, Oscar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Welch, Ken
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Effect of irradiated TiO2/H2O2 suspensions on Staphylococcus epidermidis biofilm2017In: European Cells and Materials, ISSN 1473-2262, E-ISSN 1473-2262Article in journal (Refereed)
  • 307.
    Janson, Oscar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Sörensen, Jan Henrik
    Doctores Sorensen OHG, Segeberger Landstr, Kiel, Germany.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Procter, Philip
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Welch, Ken
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Evaluation of an alkali-treated and hydroxyapatite-coated orthopedic implant loaded with tobramycin2019In: Journal of biomaterials applications, ISSN 0885-3282, E-ISSN 1530-8022, Vol. 34, no 5, p. 699-720, article id UNSP 0885328219867968Article in journal (Refereed)
    Abstract [en]

    An approximately 1-µm thick hydroxyapatite coating was biomimetically deposited on an alkali-treated, commercially available orthopedic screw surface (type II anodized titanium). Tobramycin loaded into the coating via a simple soaking method was shown to provide a sustained release above the minimal inhibitory concentration 0.2 µg/µl for up to two days. Agar diffusion tests showed that the tobramycin-loaded coating was able to produce a zone of inhibition against Staphylococcus aureus for up to five days. Biocompatibility testing using outgrowth endothelial cells and primary osteoblasts suggested that good cell compatibility of the coating can be expected in vivo. A rabbit distal femur condyle model was used for in vivo evaluation of the antibacterial efficacy of the tobramycin-loaded coating, and this pilot study showed that the release of tobramycin was sufficient to locally eliminate very large amounts of bacteria in vivo (inoculation dose 104–105 CFU S. aureus/test site).

  • 308.
    Janson, Oscar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Unosson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Welch, Ken
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Effects on organic degradation in the TiO2/H2O2/UV-Vis system2015In: 8th Annual meeting of the Scandinavian Society for Biomaterials Proceeding, 2015Conference paper (Refereed)
  • 309.
    Janson, Oscar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Unosson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Welch, Ken
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Organic degradation potential of a TiO2/H2O2/UV-Vis system for dental applications2017In: Journal of Dentistry, ISSN 0300-5712, E-ISSN 1879-176X, Vol. 67, p. 53-57Article in journal (Refereed)
    Abstract [en]

    Objectives

    The combination of TiO2 and H2O2 under light activation constitutes a promising method for disinfection of dental prosthetics and implants, due to production of reactive oxygen species (ROS). The aim of this work was to investigate the organic degradation ability of TiO2 particles in combination with H2O2 and under light activation utilizing the organic dye rhodamine B (RhB).

    Methods

    Five different types of TiO2 particles, consisting of anatase, rutile, or a mixture of these crystalline phases, were combined with H2O2 and RhB, and subsequently exposed to UV (365 nm) or visible (405 nm) light at an irradiance of 2.1 mW/cm2.

    Results

    It was found that rutile in combination with low concentrations of H2O2 (1.0–3.5 mM) resulted in a degradation of RhB of 96% and 77% after 10 min exposure to 365 nm and 405 nm light, respectively, which was the highest degradation of all test groups. Control measurements performed without light irradiation or irradiation at 470 nm, or without TiO2 particles resulted in little or no degradation of RhB.

    Conclusions

    Low H2O2 concentrations (1.0 mM–3.5 mM) and visible light (405 nm) used in combination with rutile TiO2 particles showed the highest RhB degradation capacity.

    Clinical significance

    A combination of TiO2 particles and H2O2 exposed to low energy UV or high energy visible light has an organic degradation capability that could be utilized in applications to kill or inactivate bacteria on medical devices such as dental implants for treatment against, e.g., peri-implantitis.

  • 310.
    Ji, Yu-Xia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Direct Formation of Thermochromic Composite Films of VO2 Nanoparticles in SiO2 Hosts2016In: 2016 Ieee 16th International Conference On Nanotechnology (IEEE-NANO), 2016, p. 823-825Conference paper (Refereed)
    Abstract [en]

    Vanadium dioxide (VO2) is a key material for modern thermochromic energy-efficient window coatings. Nanocomposite VO2-SiO2 films were fabricated by reactive magnetron sputtering. VO2 nanoparticles with grain sizes of about 100 nm were distributed uniformly in the SiO2 host, and the composite film showed excellent thermochromic properties with plasmonic effect.

  • 311.
    Jiao, Mingzhi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Nguyen, Duc Hoa
    Nguyen, Van Duy
    Nguyen, Van Hieu
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Nguyen, Hugo
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Controlled Synthesis and Understanding of GrowthMechanism: Parameters for Atmospheric PressureHydrothermal Synthesis of Ultrathin SecondaryZnO Nanowires2016In: Journal of Scientific Research and Reports, ISSN 2320-0227, E-ISSN 2320-0227, Vol. 9, no 5, p. 1-10Article in journal (Refereed)
    Abstract [en]

    Synthesis of ultrathin ZnO nanowires gains great attention from research community because oftheir large potential in applications involving optoelectronics and sensors. In this study, a lowpressure and low-temperature hydrothermal synthesis of ultrathin ZnO nanowires is studied tounderstand the growth mechanisms better. To achieve this aim, an about 10 nm thin Zn seed layerwas sputter-deposited on a silicon (100) wafer for the hydrothermal growth of ZnO nanowires in anequimolar aqueous solution of Zn(NO3)2 and hexamethylenetetramine. X-ray diffraction analysis confirmed that the Zn layer was self-oxidized into ZnO in air soon after deposition and thenfunctioned as the seed for the preferred growth of c-oriented ZnO nanorods. Different growthconditions were investigated to identify how concentration, temperature, and time influence the finalmorphology of the synthesized ZnO nanostructures. It was found that under the atmosphericpressure, concentration and temperature have to be higher than 0.0025 M and 50°C, respectively,for the ZnO nanorods to nucleate and grow densely. Low concentration gives sparse and randomlyoriented nanorods, whereas high concentration gives dense and vertical nanorods. Ultrathin ZnOsecondary nanowires with an average diameter of less than 20 nm were successfully synthesizedin a solution with concentration of 0.005 M at 90°C for about 16 h. By analyzing the scanningelectron microscopy images of the ZnO nanostructures obtained at different growth conditions, amechanism is proposed for the growth of the ultrathin secondary ZnO nanowires. This findingprovides a cost-effective and straightforward pathway to prepare ultrathin ZnO nanowires.

  • 312. Johansson, Christer
    et al.
    Gómez de La Torre, Teresa Zardán
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Sensitive magnetic biodetection using magnetic multi-core nanoparticles and RCA coils2016In: 11th International Conference on the Scientific and Clinical Applications of Magnetic Carriers, 2016Conference paper (Refereed)
  • 313. Johansson, Christer
    et al.
    Prieto Astalan, Andrea
    Ahrentorp, Fredrik
    Jonasson, C.
    Blomgren, Jakob
    Zárdan Gómez de la Torre, Teresa
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömberg, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Magnetic Properties of Magnetic Multi-Core particles2012Conference paper (Refereed)
  • 314.
    Johansson, Malin B.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Edvinsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Bitter, S
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Eriksson, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Johansson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Göthelid, Mats
    Boschloo, Gerrit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    From Quantum Dots to Micro Crystals: Organolead TriiodidePerovskite Crystal Growth from Isopropanol Solution2016In: ECS Journal of Solid State Science and Technology, ISSN 2162-8769, E-ISSN 2162-8777, Vol. 5, no 10, p. P614-P620Article in journal (Refereed)
    Abstract [en]

    The growth mechanism and dependence on precursor conditions are vital for creation of high quality crystalline materials in many fields. Here the growth from nano sized quantum dots to micro crystalline methyl ammonium lead tri-iodide (MAPbI(3)) perovskites prepared from isopropanol solution are reported. Isopropanol is more environmental friendly compared to the commonly used solvents DMF or DMSO, both with relatively high toxicity and the proposed method can be a useful new route to prepare hybrid perovskites. Three different molar ratios of MAPbI3 perovskite solution (MAI:PbI2 of 1: 1, 2: 1 and 0.5: 1) were applied to give insights in the crystal formation mechanism also under non-stoichiometric conditions. Perovskite crystal growth is followed by TEM. From XRD powder diffraction the lattice constants have been determined and compared with results from electron diffraction (ED). Interestingly, there seems to be an occurrence of the cubic phase besides the common tetragonal phase at room temperature.

  • 315.
    Johansson, Malin B
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Österlund, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Structural and optical properties of visible active photocatalytic WO3 thin films prepared by reactive dc magnetron sputtering2012In: Journal of Materials Research, ISSN 0884-2914, E-ISSN 2044-5326, Vol. 27, no 24, p. 3130-3140Article in journal (Refereed)
    Abstract [en]

    Nanostructured tungsten trioxide films were prepared by reactive dc magnetron sputteringat different working pressures P-tot = 1-4 Pa. The films were characterized by scanning electron microscopy, x-ray diffraction, Rutherford backscattering spectroscopy, Raman spectroscopy, and ultraviolet-visible spectrophotometry. The films were found to exhibit predominantly monoclinic structures and have similar band gap, E-g approximate to 2.8 eV, with a pronounced Urbach tail extending down to 2.5 eV. At low P-tot, strained film structures formed, which were slightly reduced and showed polaron absorption in the near-infrared region. The photodegradation rate of stearic acid was found to correlate with the stoichiometry and polaron absorption. This is explained by a recombination mechanism, whereby photoexcited electron-hole pairs recombine with polaron states in the band gap. The quantum yield decreased by 50% for photon energies close to E-g due to photoexcitations to band gap states lying below the O-2 affinity level.

  • 316.
    Johansson, S
    et al.
    Chalmers University of Technology.
    Österlund, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Kasemo, B
    Chalmers University of Technology.
    CO oxidation bistability diagrams for Pt/CeOx and Pt/SiO2 model catalysts prepared by electron-beam lithography2001In: Journal of Catalysis, ISSN 0021-9517, E-ISSN 1090-2694, Vol. 201, no 2, p. 275-285Article in journal (Refereed)
    Abstract [en]

    The CO oxidation bistability diagrams (i.e., the interval of gas mixing ratio beta drop P-CO/(P-CO + P-O2) vs temperature for which a bistability exists) have been determined for different electron beam lithography (EBL) fabricated supported model catalysts. Three different samples were studied, one Pt/SiO2 sample and two Pt/CeOx samples, where the support type, particle size, and interface length were varied independently. The kinetic bistability is an inherent property of the CO oxidation on Pt at certain gas mixtures and temperatures, and we find that the actual position of the bistable region is a very sensitive tool to measure differences in reaction kinetics on different samples. The bistable region is shifted considerably along the gas mixing ratio axis, beta, between the three samples (at constant temperature). Simulations show that the experimental results can be understood by introducing an oxygen reactant supply via the CeOx, support (spillover), which does not exist for SiO2. This extra supply of oxygen will maintain a high CO conversion rate up to higher relative CO partial pressures on ceria samples (by suppressing the CO poisoning effect). Energy barriers for O diffusion on CeOx, and the attachment across the Pt/CeOx interface have been estimated. The formation of a less reactive Pt state under oxidizing conditions is discussed. (C) 2001 Academic Press.

  • 317.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Micro- and Nanomanipulation for Nanomanufacturing2014In: Encyclopedia of Nanotechnology / [ed] Bhushan, Bharat, springer , 2014, p. 1-17Chapter in book (Refereed)
  • 318.
    Johnson, William B.
    et al.
    W. L. Gore & Associates.
    Worrell, Wayne L.
    University of Pennsylvania.
    Niklasson, Gunnar A
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Malmgren, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Sundaram, S K
    Alfred University.
    Solid-State Devices: Impedance Response of Electrochromic Materials and Devices2018In: IMPEDANCE SPECTROSCOPY: Theory, Experiment, and Applications / [ed] Evgenij Barsoukov and J. Ross Macdonald, Hoboken,: John Wiley & Sons, 2018, 3rd, p. 247-291Chapter in book (Refereed)
  • 319. Jonsson, A. K.
    et al.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Niklasson, G. A.
    Li intercalation in zirconium dioxide films2000In: Diffusion and Defect Data. Pt A Defect and Diffusion Forum, Vol. 177, p. 51-58Article in journal (Refereed)
  • 320.
    Jorner, Kjell
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Dreos, Ambra
    Chalmers, Dept Chem & Chem Engn, Kemigarden 4, SE-41296 Gothenburg, Sweden..
    Emanuelsson, Rikard
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    El Bakouri, Ouissam
    Univ Girona, Dept Quim, IQCC, Campus Montilivi, Girona 17003, Spain..
    Fernández Galván, Ignacio
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry. Uppsala Univ, UC3, Box 523, SE-75120 Uppsala, Sweden..
    Borjesson, Karl
    Chalmers, Dept Chem & Chem Engn, Kemigarden 4, SE-41296 Gothenburg, Sweden.;Univ Gothenburg, Dept Chem & Mol Biol, Kemigarden 4, SE-41296 Gothenburg, Sweden..
    Feixas, Ferran
    Univ Girona, Dept Quim, IQCC, Campus Montilivi, Girona 17003, Spain..
    Lindh, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry. Uppsala Univ, UC3, Box 523, SE-75120 Uppsala, Sweden..
    Zietz, Burkhard
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Moth-Poulsen, Kasper
    Chalmers, Dept Chem & Chem Engn, Kemigarden 4, SE-41296 Gothenburg, Sweden..
    Ottosson, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Unraveling factors leading to efficient norbornadiene-quadricyclane molecular solar-thermal energy storage systems2017In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 5, no 24, p. 12369-12378Article in journal (Refereed)
    Abstract [en]

    Developing norbornadiene-quadricyclane (NBD-QC) systems for molecular solar-thermal (MOST) energy storage is often a process of trial and error. By studying a series of norbornadienes (NBD-R-2) doubly substituted at the C7-position with R = H, Me, and iPr, we untangle the interrelated factors affecting MOST performance through a combination of experiment and theory. Increasing the steric bulk along the NBD-R-2 series gave higher quantum yields, slightly red-shifted absorptions, and longer thermal lifetimes of the energy-rich QC isomer. However, these advantages are counterbalanced by lower energy storage capacities, and overall R = Me appears most promising for short-term MOST applications. Computationally we find that it is the destabilization of the NBD isomer over the QC isomer with increasing steric bulk that is responsible for most of the observed trends and we can also predict the relative quantum yields by characterizing the S-1/S-0 conical intersections. The significantly increased thermal half-life of NBD-iPr(2) is caused by a higher activation entropy, highlighting a novel strategy to improve thermal half-lives of MOST compounds and other photo-switchable molecules without affecting their electronic properties. The potential of the NBD-R-2 compounds in devices is also explored, demonstrating a solar energy storage efficiency of up to 0.2%. Finally, we show how the insights gained in this study can be used to identify strategies to improve already existing NBD-QC systems.

  • 321.
    Josefsson, Gabriella
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Chinga-Carrasco, Gary
    Paper and Fiber Research Institute (PFI AS), Trondheim, Norway.
    Gamstedt, Kristofer
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Elastic models coupling the cellulose nanofibril to the macroscopic film level2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 71, p. 58091-58099Article in journal (Refereed)
    Abstract [en]

    The mechanical behaviour of cellulose nanofibrils is typically characterized by casting thin films and performing tensile tests on strips cut from these films. When comparing the stiffness of different films, the stiffness of the nanofibrils is only qualitatively and indirectly compared. This study provides some schemes based on various models of fibre networks, or laminated films, which can be used to assess the inherent stiffness of the nanofibrils from the stiffness of the films. Films of cellulose nanofibrils from different raw materials were manufactured and the elastic properties were measured. The expressions relating the nanofibril stiffness and the film stiffness were compared for the presented models. A model based on classical laminate theory showed the best balance between simplicity and adequacy of the underlying assumptions among the presented models. Using this model, the contributing nanofibril stiffness was found to range from 20 to 27 GPa. The nanofibril stiffness was also calculated from mechanical properties of nanofibril films found in the literature and compared with measurements from independent test methods of nanofibril stiffness. All stiffness values were found to be comparable and within the same order of magnitude.

  • 322.
    Jämstorp, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyström, Gustav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    On the self-discharge and degradation of polypyrrole electrodes for energy storage2011In: MRS Spring conference, San Francisco, 2011Conference paper (Refereed)
  • 323.
    Jämstorp, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Bredenberg, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Influence of drug distribution and solubility on release from geopolymer pellets: A finite element method study2012In: Journal of Pharmaceutical Sciences, ISSN 0022-3549, E-ISSN 1520-6017, Vol. 101, no 5, p. 1803-1810Article in journal (Refereed)
    Abstract [en]

    This study investigates the influence of drug solubility and distribution on its release from inert geopolymer pellets of three different sizes (1.5 × 1.5, 3 × 6, and 6 × 6 mm), having the same geopolymer composition and containing highly potent opioid fentanyl, sumatriptan, theophylline, or saccharin. Scanning electron microscopy, nitrogen sorption, drug solubility, permeation, and release experiments were performed, and estimates of the drug diffusion coefficients and solubilities in the geopolymer matrix were derived with the aid of finite element method (FEM). FEM was further employed to investigate the effect of a nonuniform drug distribution on the drug release profile. When inspecting the release profiles for each drug, it was observed that their solubilities in the geopolymer matrix imposed a much greater influence on the drug release rate than their diffusion coefficients. Concentrating the initial drug load in FEM into nonuniformly distributed drug regions inside the matrix created drug release profiles that more closely resembled experimental data than an FEM-simulated uniform drug distribution did. The presented FEM simulations and visualization of drug release from geopolymers under varying initial and dynamic conditions should open up for more systematic studies of additional factors that influence the drug release profile from porous delivery vehicles.

  • 324.
    Kaden, Heike
    et al.
    Karlsruhe Institute of Technology.
    Königer, Franz
    Karlsruhe Institute of Technology.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Emmerich, Katja
    Karlsruhe Institute of Technology.
    Low-frequency dielectric properties of three bentonites at different adsorbed water states2013In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 411, p. 16-26Article in journal (Refereed)
    Abstract [en]

    Three bentonites of varying smectite content were investigated by dielectric spectroscopy in the frequency range 10(-4) to 10(6)Hz after storage at well-defined humidities. The identification of relaxation processes from complex permittivity measurements was difficult, since conductivity effects were superimposed on the underlying relaxations. Relaxation peaks revealed by the dissipation factor indicated the occurrence of interfacial processes between 10(2) and 10(6) Hz. The intensity of the polarization of the electrochemical double-layer at the clay-water interface was promoted by increasing water content and was shifted to higher frequencies the higher the water content in the bentonites. Below ∼1Hz, electrode polarization (EP) was shown to be a participating process with capacitance values ranging from 0.6(*)10(-3) to 7.3(*)10(-3)F due to the accumulated charges. An equivalent circuit model was introduced that successfully described the low-frequency dielectric behavior of bentonites at low moisture levels. An included series R-CPE connection was used to describe the double-layer relaxation. At water contents up to 17%, the bulk resistivity was mainly influenced by smectite content and cation exchange capacity, whereas at water contents of ⩾19%, interlayer occupation and hydration state became more important.

  • 325. Kalabukhov, A
    et al.
    Gómez de La Torre, Teresa Zardán
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Winkler, Dag
    Chalmers.
    FLU-ID- Bioassays for fast and sensitive detection of influenza viruses using ultra-sensitive magnetometry and magnetic nanoparticles2017In: Programme conference in Medical Bioengineering 2017 / [ed] Stiftelsen för strategisk Forskning, Stockholm: Stiftelsen för strategisk Forskning , 2017Conference paper (Refereed)
  • 326. Kalabukhov, A.
    et al.
    Jesorka, A.
    Sanz-Velasco, A.
    Winkler, Dag
    Schneiderman, J.
    Blomgren, J
    Johansson, Christer
    Ahlford, Annika
    Nilsson, Mats
    Albert, Jan
    Gómez de La Torre, Teresa Zardán
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Development of nano-magnetic bioassay for detection of pandemic influenza2016In: Biosensors 2016, 26th Anniversary World Congress on Biosensors 25-27 May 2016 | Swedish Exhibition and Congress Centre, Gothenburg, Sweden, 2016Conference paper (Refereed)
  • 327. Kalabukhov, A.
    et al.
    Sepehri, S.
    Chukharkin, M
    Kustanovich, K
    Jesorka, Aldo
    Schneiderman, J
    Blomgren, Jacob
    Johansson, Christer
    Nilsson, Mats
    Gómez de La Torre, Teresa Zardán
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Winkler, Dag
    Chalmers.
    Development of ultra-sensitive magnetic sensor technologies for bioassays using magnetic multi-core nanoparticles and RCA coils2017In: Programme conference in Medical Bioengineering 2017 / [ed] Stiftelsen för Strategisk Forskning, Stockholm: Stiftelsen för Strategisk Forskning , 2017Conference paper (Refereed)
  • 328. Kalabukhov, A
    et al.
    Winkler, Dag
    Gómez de La Torre, Teresa Zardán
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    FLU-ID:Development of a low-cost and portable nano-diagnostics unit for detection of pandemic influenza2017In: Programme conference in Medical Bioengineering 2017 / [ed] Stiftelsen för strategisk forskning, Stockholm: Stiftelsen för strategisk forskning , 2017Conference paper (Refereed)
  • 329. Kalabukhov, A.
    et al.
    Winkler, Dag
    Zardán Gómez de la Torre, Teresa
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    FLU-ID: Development of a low-cost and portable nano-diagnostics unit for detection of pandemic influenza2014In: 16th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics & 10th Medicinteknikdagarna, 2014Conference paper (Refereed)
  • 330.
    Kamalakar, M. Venkata
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics. Chalmers, Dept Microtechnol & Nanosci, SE-41296 Gothenburg, Sweden..
    Dankert, Andre
    Chalmers, Dept Microtechnol & Nanosci, SE-41296 Gothenburg, Sweden..
    Kelly, Paul J.
    Univ Twente, Fac Sci & Technol, POB 217, NL-7500 AE Enschede, Netherlands.;Univ Twente, MESA Inst Nanotechnol, POB 217, NL-7500 AE Enschede, Netherlands..
    Dash, Saroj P.
    Chalmers, Dept Microtechnol & Nanosci, SE-41296 Gothenburg, Sweden..
    Inversion of Spin Signal and Spin Filtering in Ferromagnet vertical bar Hexagonal Boron Nitride-Graphene van der Waals Heterostructures2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 21168Article in journal (Refereed)
    Abstract [en]

    Two dimensional atomically thin crystals of graphene and its insulating isomorph hexagonal boron nitride (h-BN) are promising materials for spintronic applications. While graphene is an ideal medium for long distance spin transport, h-BN is an insulating tunnel barrier that has potential for efficient spin polarized tunneling from ferromagnets. Here, we demonstrate the spin filtering effect in cobalt vertical bar few layer h-BN vertical bar graphene junctions leading to a large negative spin polarization in graphene at room temperature. Through nonlocal pure spin transport and Hanle precession measurements performed on devices with different interface barrier conditions, we associate the negative spin polarization with high resistance few layer h-BN vertical bar ferromagnet contacts. Detailed bias and gate dependent measurements reinforce the robustness of the effect in our devices. These spintronic effects in two-dimensional van der Waals heterostructures hold promise for future spin based logic and memory applications.

  • 331.
    Karlsson, Christoffer
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Conducting Redox Polymers for Electrical Energy Storage: Backbone - Substituent Interactions in Quinone Polypyrrole Model Systems2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Organic electrical energy storage (EES) is a growing field of research that is expected to play an important role in the future, as the need for sustainable EES increases. Conducting redox polymers (CRPs), i.e. conducting polymers with incorporated redox active moieties e.g. as pendant groups (PGs), are proposed as a promising class of compounds for this purpose. Redox cycling of the PGs can be utilized for high charge storage capacity, while the conducting polymer backbone provides fast charge transport through the material. Some of the major challenges with small-molecule systems for EES could be solved by using CRPs, e.g. capacity fading due to dissolution of the active compound, and high resistance due to slow charge transport between molecules. The latter issue is often solved by adding large amounts of conducting additives to the active material, drastically lowering the specific capacity. In this project, CRPs are shown to be able to function in battery cells without any additives, making both high capacity and high power possible. Although several CRPs have been reported in the literature, very few detailed studies have been conducted on the electrochemical processes of the two systems (i.e. the conducting polymer backbone and the redox active PGs). An important factor to consider in CRP design is the possibility for interaction between the two redox systems, which could be either beneficial or detrimental to the function as EES material. In this thesis, CRP model systems composed of hydroquinone functionalized polypyrrole have been studied, and they exhibit separate redox reactions for the PGs and the backbone, overlapping in potential. Significant interaction between them was observed, as oxidation of the PGs has severe impact on the backbone: When the oxidized and hydrophobic p-benzoquinone PGs are formed, they pack and force the polymer backbone to twist, localizing the bipolarons, and decreasing the conductivity. This is accompanied by a contraction of the polymer film and expulsion of electrolyte. Overall, the interaction in these polymers is destructive for their EES function, and it could be eliminated by introduction of a long linker unit between the PGs and the backbone.

    List of papers
    1. Computational Electrochemistry Study of 16 Isoindole-4,7-diones as Candidates for Organic Cathode Materials
    Open this publication in new window or tab >>Computational Electrochemistry Study of 16 Isoindole-4,7-diones as Candidates for Organic Cathode Materials
    2012 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 116, no 5, p. 3793-3801Article in journal (Refereed) Published
    Abstract [en]

    Prediction of the redox behavior of electroactive molecules enables screening of a variety of compounds and can serve as a guideline in the search for organic molecules for use as cathode materials in, for example, Li ion batteries. In this study, we present a computational strategy, based on density functional theory, to calculate redox potentials and acid dissociation constants for a series of 16 isoindole-4,7-dione (IID) derivatives. The calculations take all possible electron and proton transfers into account, and the results were found to correlate very well with electrochemical and spectroscopic measurements. The possibility of polymerizing the IID derivatives was also assessed computationally, as polymerization serves as a straightforward route to immobilize the active material. Three of the considered IIDs (5,6-dicyano-2-methyl-isoindole-4,7-dione, 5,6-dihydroxy-2-methyl-isoindole-4,7-dione, and 2-methyl-5-(trifluoromethyl)-isoindole-4,7-dione) are predicted to be particularly interesting for making polymers for organic cathodes because these are calculated to have high redox potentials and high specific capacities and to be readily polymerizable. The presented strategy is general and can be applied in the prediction of the electrochemical behavior of quinones as well as other systems involving proton and electron transfers.

    Place, publisher, year, edition, pages
    American Chemical Society, 2012
    National Category
    Other Chemistry Topics Nano Technology
    Research subject
    Engineering Science with specialization in Nanotechnology and Functional Materials
    Identifiers
    urn:nbn:se:uu:diva-168889 (URN)10.1021/jp211851f (DOI)000299985300073 ()
    Available from: 2012-02-17 Created: 2012-02-17 Last updated: 2018-11-05Bibliographically approved
    2. Investigation of the Redox Chemistry of Isoindole-4,7-diones
    Open this publication in new window or tab >>Investigation of the Redox Chemistry of Isoindole-4,7-diones
    2013 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 117, no 2, p. 894-901Article in journal (Refereed) Published
    Abstract [en]

    Quinone derivatives have been proposed as active components in lithium ion battery (LIB) electrode materials. In this work the electrochemistry of a series of substituted isoindole-4,7-diones (IIDs) was investigated. Three new IID derivatives were synthesized and characterized by various electrochemical and spectroscopic techniques. Polymerization was attempted to achieve a conducting polymer with redox active quinone side groups, which would be advantageous in a LIB application. A combination of in situ spectroelectrochemical measurements and density functional theory (DFT) calculations was used to investigate the proton coupled redox reactions of the IIDs. Results from a previous computational study of the IIDs were compared with experimental data here, and the agreement was very good. The energy of the spectroscopic transitions in the UV and in the visible region showed different correlation with redox potential and quinone substituent in the series of IIDs. This behavior was rationalized by examination of the involved molecular orbitals. The results indicated that the properties of the quinone unit, such as the redox potential, could be selectively varied by substitution.

    National Category
    Physical Chemistry Engineering and Technology
    Research subject
    Engineering Science with specialization in Nanotechnology and Functional Materials
    Identifiers
    urn:nbn:se:uu:diva-192605 (URN)10.1021/jp311009z (DOI)000313932800017 ()
    Available from: 2013-01-23 Created: 2013-01-23 Last updated: 2017-12-06Bibliographically approved
    3. Polymer–Pendant Interactions in Poly(pyrrol-3-ylhydroquinone): A Solution for the Use of Conducting Polymers at Stable Conditions
    Open this publication in new window or tab >>Polymer–Pendant Interactions in Poly(pyrrol-3-ylhydroquinone): A Solution for the Use of Conducting Polymers at Stable Conditions
    Show others...
    2013 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 117, no 45, p. 23558-23567Article in journal (Refereed) Published
    Abstract [en]

    While various organic molecules have been suggested as environmentally friendly alternatives to inorganic electrode materials for lithium ion batteries, most of them suffer from slow kinetics as well as capacity fading due to dissolution. Herein we present the synthesis of poly(pyrrol-3-ylhydroquinone) (PPyQ), a polypyrrole (PPy) derivative with pending hydroquinone groups, for investigation of the use of a conducting polymer to immobilize redox active quinone units. This strategy eliminates dissolution of the active material while also increasing the conductivity. The quinone pending groups in PPyQ cycle reversibly in the potential region where the polymer backbone is conducting and chemically stable. In situ spectroelectrochemistry on PPyQ films reveals UV/vis transitions inherent to PPy, as well as quinone centered transitions, allowing detailed investigation of the interplay between the polymer doping process and the quinone redox conversion. Intriguingly, it is found that the charging of the PPy backbone halts during the redox reaction of the quinone pending groups. This opens up for the possibility of using PPy at low and constant doping levels while utilizing the charge storage capacity of the quinone pending groups when creating electric energy storage materials based on sustainable and renewable components.

    National Category
    Physical Chemistry Engineering and Technology
    Research subject
    Engineering Science with specialization in Nanotechnology and Functional Materials
    Identifiers
    urn:nbn:se:uu:diva-210983 (URN)10.1021/jp408567h (DOI)000327110500015 ()
    Available from: 2013-11-18 Created: 2013-11-18 Last updated: 2017-12-06Bibliographically approved
    4. Probing Polymer-Pendant Interactions in the Conducting Redox Polymer Poly(pyrrol-3-ylhydroquinone)
    Open this publication in new window or tab >>Probing Polymer-Pendant Interactions in the Conducting Redox Polymer Poly(pyrrol-3-ylhydroquinone)
    Show others...
    2014 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 118, no 41, p. 23499-23508Article in journal (Refereed) Published
    Abstract [en]

    Conducting polymers with redox active pendant groups show properties typical of both conducting polymers (i.e., capacitive charging and intrinsic conductivity) and redox polymers (i.e., electrochemical surface response at the formal potential of the pendant groups). The two components can also exert significant interaction on each other during their separate electrochemical reactions. In poly(pyrrol-3-ylhydroquinone), a polypyrrole derivative functionalized with hydroquinone units, the redox conversion of the pendant groups has a large impact on the polymer backbone. This interaction is manifested by a loss of bipolaron states during the hydroquinone oxidation, leading to a decreasing p-doping level with increasing potential, something which, to the best of our knowledge, has never been observed for a conducting polymer. Another effect is a contraction of the polymer film, and subsequent mass loss due to solvent expulsion upon hydroquinone oxidation, which counteracts the normal swelling of polypyrrole with increased potential. The conducting redox polymer under investigation has been synthesized via two routes, leading to different fractions of subunits bearing redox active hydroquinone groups. While the redox potentials are unaffected by the synthesis route, the backbone/pendant group interaction varies notably depending on the degree of quinone functionalization. This type of polymers could find use in, e.g., organic energy storage materials, since the polymer backbone both increases the electronic conductivity and prevents dissolution of the active material, as well as in actuator application, due to polymer contraction over the relatively narrow potential region where the pendant group redox chemistry occurs.

    National Category
    Physical Chemistry Engineering and Technology
    Research subject
    Engineering Science with specialization in Nanotechnology and Functional Materials
    Identifiers
    urn:nbn:se:uu:diva-230486 (URN)10.1021/jp506821z (DOI)000343333600007 ()
    Available from: 2014-09-10 Created: 2014-08-26 Last updated: 2017-12-05Bibliographically approved
    5. Quinone Pendant Group Kinetics in Poly(pyrrol-3-ylhydroquinone)
    Open this publication in new window or tab >>Quinone Pendant Group Kinetics in Poly(pyrrol-3-ylhydroquinone)
    Show others...
    2014 (English)In: Journal of Electroanalytical Chemistry, ISSN 0022-0728, E-ISSN 1873-2569, Vol. 735, p. 95-98Article in journal (Refereed) Published
    Abstract [en]

    Herein, we investigate the kinetics of the redox processes occurring in acidic aqueous electrolyte in electropolymerized poly(pyrrol-3-ylhydroquinone), which has been proposed for electrical energy storage applications. The redox conversion of the pendant groups is found to be limited by the quinone redox kinetics in thin films, rather than by the conduction through the polypyrrole backbone. Rate constants for the elementary steps involved in this 2e, 2H+ process are reported. As the films are made thicker, a gradual transition to a diffusion limited reaction is observed. The origin of the diffusion process, as well as the elementary reaction steps limiting the pendant group redox conversion is analyzed using DFT computations. The fact that the electron transport through the thin film conducting polymer backbone is not limiting the quinone reaction kinetics should allow for design of battery electrodes with high rate capabilities based on the studied material.

    National Category
    Physical Chemistry Engineering and Technology
    Research subject
    Engineering Science with specialization in Nanotechnology and Functional Materials
    Identifiers
    urn:nbn:se:uu:diva-230487 (URN)10.1016/j.jelechem.2014.10.013 (DOI)000346214800015 ()
    Available from: 2014-09-10 Created: 2014-08-26 Last updated: 2017-12-05Bibliographically approved
    6. Impact of Linker in Polypyrrole/Quinone Conducting Redox Polymers
    Open this publication in new window or tab >>Impact of Linker in Polypyrrole/Quinone Conducting Redox Polymers
    Show others...
    2015 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 15, p. 11309-11316Article in journal (Refereed) Published
    Abstract [en]

    Organic conducting redox polymers are being investigated as the active component for secondary battery applications, as they have the potential to solve two of the main problems with small molecule-based organic electrodes for electrical energy storage, viz dissolution of the active compound in the electrolyte, and slow charge transport through the material. Herein we report the synthesis of a series of conducting redox polymers based on polypyrrole with hydroquinone pendant groups that are attached to the backbone via different linkers, and we investigate the impact of the linker on the interaction between the backbone and the pendant groups. For the directly linked polymer, oxidation of the pendant groups leads to a decrease of bipolaron absorbance, as well as a decrease in mass of the polymer film, both of which are reversible. The origin of these effects is discussed in light of the influence of the linker unit, electrolyte polarity, and electrolyte salt. For the longest linkers in the series, no interaction was observed, which was deemed the most beneficial situation for energy storage applications, as the energy storage capacity of the pendant groups can be utilized without disturbing the conductivity of the polymer backbone.

    National Category
    Physical Chemistry Engineering and Technology Nano Technology
    Research subject
    Engineering Science with specialization in Nanotechnology and Functional Materials
    Identifiers
    urn:nbn:se:uu:diva-230488 (URN)10.1039/c4ra15708g (DOI)000348986900057 ()
    Available from: 2014-09-10 Created: 2014-08-26 Last updated: 2017-12-05
  • 332.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Ion- and Electron Transport in Pyrrole/Quinone Conducting Redox Polymers Investigated by In Situ Conductivity Methods2015In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 179, p. 336-342Article in journal (Refereed)
    Abstract [en]

    Polypyrrole functionalized with redox active pendant groups constitutes a so called conducting redox polymer, and functions both as a conducting polymer and as a redox polymer. The electrochemical response reveals capacitive charging of the conducting backbone as well as redox cycling of the pendant groups. While the backbone provides an electrically conducting matrix for fast electron transport through the material, the pendant groups offer a large charge storage capacity, much greater than that of polypyrrole itself. We have investigated such polypyrrole-hydroquinone conducting redox polymers, with focus on their in situ conductivity during electrochemical cycling, in order to understand the charge transport mechanisms in this type of system. The most notable feature is that oxidation of the pendant groups leads to a large decrease in the polymer conductivity. The causes of this phenomenon are discussed, as well as the rate limitations of fast redox cycling of the polymer, which are investigated through a combination of bipotentiostat cyclic voltammetry and potential steps of polymer films on interdigitated array electrodes.

  • 333.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Charge transport in pyrrole/quinone conducting redox polymers2014Conference paper (Refereed)
  • 334.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Conducting Redox Polymers – New Candidates for Organic Electrode Materials2013Conference paper (Refereed)
  • 335.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Conducting Redox Polymers – New Candidates for Organic Electrode Materials2014Conference paper (Refereed)
  • 336.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Impact of Linker in Polypyrrole/Quinone Conducting Redox Polymers2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 15, p. 11309-11316Article in journal (Refereed)
    Abstract [en]

    Organic conducting redox polymers are being investigated as the active component for secondary battery applications, as they have the potential to solve two of the main problems with small molecule-based organic electrodes for electrical energy storage, viz dissolution of the active compound in the electrolyte, and slow charge transport through the material. Herein we report the synthesis of a series of conducting redox polymers based on polypyrrole with hydroquinone pendant groups that are attached to the backbone via different linkers, and we investigate the impact of the linker on the interaction between the backbone and the pendant groups. For the directly linked polymer, oxidation of the pendant groups leads to a decrease of bipolaron absorbance, as well as a decrease in mass of the polymer film, both of which are reversible. The origin of these effects is discussed in light of the influence of the linker unit, electrolyte polarity, and electrolyte salt. For the longest linkers in the series, no interaction was observed, which was deemed the most beneficial situation for energy storage applications, as the energy storage capacity of the pendant groups can be utilized without disturbing the conductivity of the polymer backbone.

  • 337.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Yang, Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Quinone pending groups on polypyrrole affect the backbone doping behavior2014Conference paper (Refereed)
  • 338.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Jämstorp, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Computational Electrochemistry Study of 16 Isoindole-4,7-diones as Candidates for Organic Cathode Materials2012In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 116, no 5, p. 3793-3801Article in journal (Refereed)
    Abstract [en]

    Prediction of the redox behavior of electroactive molecules enables screening of a variety of compounds and can serve as a guideline in the search for organic molecules for use as cathode materials in, for example, Li ion batteries. In this study, we present a computational strategy, based on density functional theory, to calculate redox potentials and acid dissociation constants for a series of 16 isoindole-4,7-dione (IID) derivatives. The calculations take all possible electron and proton transfers into account, and the results were found to correlate very well with electrochemical and spectroscopic measurements. The possibility of polymerizing the IID derivatives was also assessed computationally, as polymerization serves as a straightforward route to immobilize the active material. Three of the considered IIDs (5,6-dicyano-2-methyl-isoindole-4,7-dione, 5,6-dihydroxy-2-methyl-isoindole-4,7-dione, and 2-methyl-5-(trifluoromethyl)-isoindole-4,7-dione) are predicted to be particularly interesting for making polymers for organic cathodes because these are calculated to have high redox potentials and high specific capacities and to be readily polymerizable. The presented strategy is general and can be applied in the prediction of the electrochemical behavior of quinones as well as other systems involving proton and electron transfers.

  • 339.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nicholas, James
    Univ South Australia, Future Ind Inst, Thin Film Coatings Grp, Adelaide, SA 5001, Australia.; Univ Bath, Dept Chem, Bath BA2 7AY, Avon, England.
    Evans, Drew
    Univ South Australia, Future Ind Inst, Thin Film Coatings Grp, Adelaide, SA 5001, Australia.
    Forsyth, Maria
    Deakin Univ, ARC Ctr Excellence Electromat Sci, Burwood 3125, Australia.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Howlett, Patrick C
    Deakin Univ, ARC Ctr Excellence Electromat Sci, Burwood 3125, Australia.
    Pozo-Gonzalo, Cristina
    Deakin Univ, ARC Ctr Excellence Electromat Sci, Burwood 3125, Australia.
    Stable Deep Doping of Vapor-Phase Polymerized Poly(3,4-ethylenedioxythiophene)/Ionic Liquid Supercapacitors.2016In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, no 16, p. 2112-2121Article in journal (Refereed)
    Abstract [en]

    Liquid-solution polymerization and vapor-phase polymerization (VPP) have been used to manufacture a series of chloride- and tosylate-doped poly(3,4-ethylenedioxythiophene) (PEDOT) carbon paper electrodes. The electrochemistry, specific capacitance, and specific charge were determined for single electrodes in 1-ethyl-3-methylimidazolium dicyanamide (emim dca) ionic liquid electrolyte. VPP-PEDOT exhibits outstanding properties with a specific capacitance higher than 300 F g(-1) , the highest value reported for a PEDOT-based conducting polymer, and doping levels as high as 0.7 charges per monomer were achieved. Furthermore, symmetric PEDOT supercapacitor cells with the emim dca electrolyte exhibited a high specific capacitance (76.4 F g(-1) ) and high specific energy (19.8 Wh kg(-1) ). A Ragone plot shows that the VPP-PEDOT cells combine the high specific power of conventional ("pure") capacitors with the high specific energy of batteries, a highly sought-after target for energy storage.

  • 340.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Olsson, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Electric Energy Storage: Conducting Redox Polymers2013Conference paper (Refereed)
  • 341.
    Karlsson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Research at Ångström Laboratory, Uppsala University and micro- and nanostructuring of semiconductor materials2015Conference paper (Refereed)
  • 342.
    Karlsson, Mikael
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Nikolajeff, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Diamond: Optic's best friend2002Conference paper (Refereed)
  • 343.
    Karlsson, Mikael
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Nikolajeff, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Integration of micro-optics with semiconductor lasers2002Conference paper (Refereed)
  • 344. Keskinen, Jari
    et al.
    Tuurala, Saara
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Kiri, Kaisa
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Flyktman, Timo
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Smolander, Maria
    Asymmetric and symmetric supercapacitors based on polypyrrole and activated carbon electrodes2015In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 203, p. 192-199Article in journal (Refereed)
    Abstract [en]

    Abstract Supercapacitors were prepared using either two polypyrrole (PPy) composite electrodes or one PPy composite and one activated carbon electrode. The PPy composite electrodes were either freestanding paper-like sheets or PPy films printed on graphite ink coated aluminium/PET laminate substrates, using Cladophora algae derived cellulose as the substrate or binder, respectively. The specific capacitance of the PPy electrodes was found to be about 200 F g−1 depending on the manufacturing method, yielding supercapacitors with capacitances between 0.45 and 3.8 F and energy efficiencies of over 90%. For an asymmetric device with activated carbon positive electrode and PPy negative electrode a capacitance loss of 5% was seen after 14300 cycles.

  • 345.
    Kim, Byung-Hyun
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Hermansson, Kersti
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Wolf, Matthew J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Kullgren, Jolla
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Broqvist, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Multiscale modelling of CeO2 nano-interfaces2017Conference paper (Other academic)
  • 346. Kirchgeorg, Robin
    et al.
    Wei, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Lee, Kiyoung
    So, Seugli
    Schmuki, Patrik
    Through-Hole, Self-Ordered Nanoporous Oxide Layers on Titanium, Niobium and Titanium–Niobium Alloys in Aqueous and Organic Nitrate Electrolytes2012In: ChemistryOpen, ISSN 2191-1363, Vol. 1, no 1, p. 21-25Article in journal (Refereed)
  • 347.
    Kiselev, A
    et al.
    Umeå University.
    Andersson, M
    Chalmers University of Technology.
    Mattsson, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Shchukarev, A
    Umeå University.
    Sjoberg, S
    Umeå University.
    Palmqvist, A
    Österlund, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Solar light decomposition of DFP on the surface of anatase and rutile TiO2 prepared by hydrothermal treatment of microemulsions2005In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 584, no 1, p. 98-105Article in journal (Refereed)
    Abstract [en]

    The photocatalytic decomposition of diisopropylfluorophosphate (DFP) over nanostructured anatase and rutile TiO2 powder was investigated by FTIR and XPS. Upon irradiation with artificial solar light DFP decomposed on both polymorphs as evidenced by FTIR. For both crystalline structures acetone and subsequently coordinated formate and carbonate were observed on the surface during the photocatalytic reaction is the isopropyl groups dissociated from DFP. XPS revealed that small amounts of phosphates and inorganic fluoride (Ti-F) gradually built up on both TiO2 surfaces, while organic F was present only on the rutile phase. From repeated cycles of intermittent DFP adsorption and irradiation measurements, the decomposition rates and formation of residuals on the surface were deduced. It was found that the overall oxidation yield is higher on anatase than rutile. The oxidation rate decreases with increasing irradiation time. an effect that is more pronounced on rutile. We find that both the difference between the polymorphs and the initial decrease of the oxidation yield can largely be explained by variations in surface area rather than poisoning by POx or F species. In particular, we observe a dramatic decrease of the specific area or rutile as a function of photocatalytic oxidation cycle. (c) 2005 Elsevier B.V. All rights reserved.

  • 348.
    Kiselev, A.
    et al.
    Umeå University.
    Mattsson, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Andersson, M.
    Chalmers University of Technology.
    Palmqvist, A E C
    Chalmers University of Technology.
    Österlund, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Adsorption and photocatalytic degradation of diisopropyl fluorophosphate and dimethyl methylphosphonate over dry and wet rutile TiO22006In: Journal of Photochemistry and Photobiology A: Chemistry, ISSN 1010-6030, E-ISSN 1873-2666, Vol. 184, no 1-2, p. 125-134Article in journal (Refereed)
    Abstract [en]

    Nanosized, crystalline rutile TiO2 was synthesized at room temperature using a microemulsion-mediated system followed by hydrothermal treatment. The formed rutile had a specific surface area of about 40 m(2) g(-1) and the rutile crystals had dimensions of about 10 nm x 150 nm, which aggregated into 200-1000nm sized bundles. The adsorption and photocatalytic degradation of diisopropyl fluorophosphate (DFP) and dimethyl methylphosphonate (DMMP) over these rutile TiO2 nanoparticles in dry and wet synthetic air was investigated by in situ diffuse reflectance Fourier transform infrared (DRIFT) spectroscopy during simulated solar light illumination. The methyl and isopropyl groups do not dissociate upon adsorption on either dry or humidified rutile nanoparticles. The F atom in DFP is, however, easily hydrolyzed and is readily dissociated upon interaction with hydroxyls on the TiO2 surfaces and leads to a destabilization of the DFP molecule. The initial solar light induced photodegradation rate for DFP and DMMP is 5.9 x 10(-4) and 1.0 x 10(-4) s(-1) in dry conditions and 8.1 x 10(-4) and 0.7 x 10(-4) s(-1) in wet conditions (corresponding to 2-3 monolayers (ML) water coverage), respectively. The main intermediate partial oxidation surface products are found to be surface bound formate-carboxylate-carbonate (R-COO-) and phosphate (R-POO-) species. Among them eta(1)-coordinated acetone and mu-formate, bicarbonate, and bidentate R-POO- moieties are detected. These surface species accumulate on the surface during the entire illumination period (60 min), and lead to a decreased total oxidation rate. Controlled humidification of the rutile surface leads to a reduction of the concentration of R-COO- intermediates, while at the same time maintaining approximately the same rate of DFP and DMMP photooxidation. The latter is due to blocking of Ti surface cation sites, which prevents the formation of strongly bonded surface compounds, in particular mu-coordinated R-COO- and R-POO- species. The findings show that, it is possible to optimize the sustained photocatalytic degradation of organic phosphorous compounds by controlled humidification of the reaction gas. (c) 2006 Elsevier B.V. All rights reserved.

  • 349. Kish, L. L.
    et al.
    Kameoka, J.
    Granqvist, C.-G.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Kish, L.-B.
    Diffusion Noise and Photonic Shot Noise at Single Molecule Fluorescence in Micro/Nano-Fluidic Channels2012Conference paper (Refereed)
  • 350. Kizling, Michal
    et al.
    Stolarczyk, Krzysztof
    Kiat, Julianna Sim Sin
    Tammela, Petter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Wang, Zhaohui
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Bilewicz, Renata
    Pseudocapacitive polypyrrole-nanocellulose composite for sugar-air enzymatic fuel cells2015In: Electrochemistry communications, ISSN 1388-2481, E-ISSN 1873-1902, Vol. 50, p. 55-59Article in journal (Refereed)
    Abstract [en]

    Efficient, new combination of a bioelectrocatalytic and a pseudocapacitive cellulose-based composite material is reported. The anode comprising Gluconobacter sp. fructose dehydrogenase physically adsorbed on Cladophora sp. Algae nanocellulose/polypyrrole composite provides large catalytic oxidation currents due to large effective surface area of the composite material, and enables storing of the charge. Supercapacitor properties are useful for larger current demands e.g. during switching on-off the devices. Mediatorless catalytic oxidation current densities as high as 14 mA cm(-2) at potentials as negative as -0.17 V vs. Ag/AgCl constitute the best anode performance without using mediators reported to date. The fuel cell with GCE cathode covered with laccase adsorbed on naphthylated multiwalled carbon nanotubes, exhibits improved parameters: open circuit voltage of 0.76 V, and maximum power density 1.6 mW cm(-2).

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