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  • 101.
    Berkowicz, Sharon
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Dynamic Stark Shaping of Molecular Fate2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The dynamic (ac) Stark effect refers to the energy shifting of electronic states induced by an oscillating electric field. Conveniently, the magnitude of the ac Stark shift scales with the square of the electric field amplitude, i.e. with light intensity. Using this fundamental effect to reshape molecular potentials, and steer the course of chemical reactions, is known as dynamic Stark control. The aim of this study was to investigate the dynamic Stark effect on the photodissociation of molecular oxygen (O2) in the Schumann-Runge continuum, SRC (130–175 nm). Absorption in the SRC leads to dissociation via the so-called B state, yielding O(1D) + O(3P), or the J state, forming O(3P) + O(3P). Both of these dissociative excited states may be well-described in terms of mixed valence and Rydberg state character, in which each of the two states are strongly coupled to a Rydberg state of similar symmetry.

    Due to the mixed character of the B and J states, simulations predict that dynamic Stark shifting of the coupled Rydberg states leads to a dramatic change in dissociation channel branching ratio, as well as a red-shift of the absorption spectrum. This study aimed at experimentally testing this theoretical prediction. A 400-nm femtosecond laser pulse was employed as a combined pump and control field, simultaneously inducing a three-photon transition into the SRC and ac Stark shifting the potentials. A detection scheme to detect the changes in absorption of the B channel with pump pulse intensity was devised and implemented. The chosen detection scheme, in which emission at 762 nm from the O2(b−X) transition is measured, in principle monitors O(1D) from the B channel via an energy transfer reaction.

    The experimental results overall show consistency between simulations and experiment. The measured 762-nm emission exhibited a pump pulse intensity-dependence that likely reflects the dynamic Stark reshaping of the excited state potentials. However, saturation is clearly present in the data, complicating data interpretation. Furthermore, deviations between experiment and simulations are large at high pulse intensities, indicating that O(1D) is additionally generated by absorption into higher excited states. Finally, structured features that deviate from the simulations at low pulse intensities may possibly be assigned to vibrational resonances to high-lying Rydberg states by four-photon absorption. 

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  • 102.
    Berkowicz, Sharon
    et al.
    KTH, School of Chemical Science and Engineering (CHE).
    Olsson, Helena
    KTH, School of Chemical Science and Engineering (CHE).
    Broberg, Henrik
    KTH, School of Chemical Science and Engineering (CHE).
    Evaluation of Amyloid Fibrils as Templates for Photon Upconversion by Sensitized Triplet-Triplet Annihilation2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In the face of global warming and shrinking resources of fossil fuels

    the interest in solar energy has increased in recent years. However,

    the low energy and cost efficiency of current solar cells has up to

    this date hindered solar energy from playing a major role on the

    energy market. Photon upconversion is the process in which light

    of low energy is converted to high energy photons. Lately, this

    phenomenon has attracted renewed interest and ongoing research

    in this field mainly focuses on solar energy applications, solar cells

    in particular. The aim of this study was to investigate and evaluate

    amyloid fibrils as nanotemplates for an upconversion system

    based on the dyes platinum octaetylporphyrin (PtOEP) and 9,10-

    diphenylanthracene (DPA). This well-known pair of organic dyes

    upconverts light in the visible spectrum through a mechanism

    known as sensitized triplet-triplet annihilation. Amyloid fibrils

    are β-sheet rich protein fibril structures, formed by self-assembly

    of peptides.

    Amyloid fibrils were prepared from whey protein isolate using heat

    and acidic solutions. Dyes were incorporated according to a wellestablished

    technique, in which dyes are grinded together with the

    protein in solid state prior to fibrillization. Photophysical properties

    of pure fibrils and dye-incorporated fibrils were studied using

    UV-VIS spectroscopy and fluorescence spectroscopy. Atomic force

    microscopy was further employed to confirm the presence of amyloid

    fibrils as well as to study fibril structure. Results indicate

    that amyloid fibrils may not be the optimal host material for the

    upconversion system PtOEP/DPA. It was found that the absorption

    and emission spectra of this system overlap to a great deal

    with that of the fibrils. Though no upconverted emission clearly

    generated by the dye system was recorded, anti-Stokes emission

    was indeed observed. Interestingly, this emission appears to be

    strongly enhanced by the presence of dyes. It is suggested that

    this emission may be attributed to the protein residues rather than

    the amyloid structure. Future studies are encouraged to further

    investigate these remarkable findings.

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  • 103.
    Bernhem, Kristoffer
    KTH, School of Chemical Science and Engineering (CHE).
    How ionic are ionic liquids?2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Ionic liquids are continuously finding more and more applications, both in research and in the industry. Many attempts have been made to find parameters that could be used to describe all ionic liquid systems. Five years ago a Japanese group applied the work of Gutmann on ionic liquids to use ionic association to describe solvation effects. The group calculated ionic association from conductivity and diffusion measurements. This report presents a direct approach through electrophoretic NMR to measure ionic association in ionic liquids.

     The report contains a brief introduction to ionic liquids and their properties as well as a short explanation of Nuclear Magnetic Resonance (NMR) spectroscopy, diffusion NMR and a more detailed explanation of electrophoretic NMR (eNMR). Experimental setups, taken from previous work by the NMR group at Physical Chemistry KTH, have been modified to allow for measurements in ionic liquid systems. The report discusses the issues that can arise when measuring eNMR in ionic liquids and suggests solutions. The method developed is principally built upon experiments on 1-butyl-3-methyl-imidazolium trifluoroacetate and is directly applicable to other ionic liquid systems. For more viscous systems than the one investigated here, slight changes will need to be made, as explained in the report.

     In order to evaluate the method developed during the project the degree of association for 1-butyl-3-methyl-imidazolium trifluoroacetate has been calculated from experimental results and results in similar values as reported by Tokuda et al.. Furthermore, the temperature variation due to Joule heating during a complete eNMR experiment was also investigated by observing change in chemical shift.

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  • 104.
    Besharat, Zahra
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Material Physics, MF. KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Halldin Stenlid, Joakim
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Soldemo, Markus
    KTH, School of Engineering Sciences (SCI), Applied Physics, Material Physics, MF.
    Marks, Kess
    Önsten, Anneli
    KTH, School of Engineering Sciences (SCI), Applied Physics, Material Physics, MF.
    Johnson, Magnus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Öström, Henrik
    Weissenrieder, Jonas
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Brinck, Tore
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Göthelid, Mats
    KTH, School of Engineering Sciences (SCI), Applied Physics, Material Physics, MF.
    Dehydrogenation of methanol on Cu2O(100) and (111)2017In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 146, no 24Article in journal (Refereed)
    Abstract [en]

    Adsorption and desorption of methanol on the (111) and (100) surfaces of  Cu2O have been studied using high-resolution photoelectron spectroscopy in the temperature range 120–620 K, in combination with density functional theorycalculations and sum frequency generation spectroscopy. The bare (100) surfaceexhibits a (3,0; 1,1) reconstruction but restructures during the adsorption process into a Cu-dimer geometry stabilized by methoxy and hydrogen binding in Cu-bridge sites. During the restructuring process, oxygen atoms from the bulk that can host hydrogen appear on the surface. Heating transforms methoxy to formaldehyde, but further dehydrogenation is limited by the stability of the surface and the limited access to surface oxygen. The (√3 × √3)R30°-reconstructed (111) surface is based on ordered surface oxygen and copper ions and vacancies, which offers a palette of adsorption and reaction sites. Already at 140 K, a mixed layer of methoxy, formaldehyde, and CHxOy is formed. Heating to room temperature leaves OCH and CHx. Thus both CH-bond breaking and CO-scission are active on this  surface at low temperature. The higher ability to dehydrogenate methanol on (111) compared to (100) is explained by the multitude of adsorption sites and, in particular, the availability of surfaceoxygen.

  • 105.
    Bełdowski, Piotr
    et al.
    Institute of Mathematics and Physics, Bydgoszcz University of Science and Technology, al. Kaliskiego 7 85-796 Bydgoszcz Poland, al. Kaliskiego 7.
    Przybyłek, Maciej
    Department of Physical Chemistry, Pharmacy Faculty, Collegium Medicum of Bydgoszcz, Nicolaus Copernicus University in Toruń, Kurpińskiego 5 85-950 Bydgoszcz Poland, Kurpińskiego 5.
    Bełdowski, Damian
    Institute of Mathematics, Jagiellonian University, Lukasiewicza 6 30-348 Kraków Poland, Lukasiewicza 6.
    Dédinaité, Andra
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Engineering Pedagogics.
    Sionkowska, Alina
    Department of Biomaterials and Cosmetics Chemistry, Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarin 7 87-100 Toruń Poland, Gagarin 7.
    Cysewski, Piotr
    Department of Physical Chemistry, Pharmacy Faculty, Collegium Medicum of Bydgoszcz, Nicolaus Copernicus University in Toruń, Kurpińskiego 5 85-950 Bydgoszcz Poland, Kurpińskiego 5.
    Claesson, Per M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Collagen type II-hyaluronan interactions - the effect of proline hydroxylation: a molecular dynamics study2022In: Journal of materials chemistry. B, ISSN 2050-750X, E-ISSN 2050-7518, Vol. 10, no 46, p. 9713-9723Article in journal (Refereed)
    Abstract [en]

    Hyaluronan-collagen composites have been employed in numerous biomedical applications. Understanding the interactions between hyaluronan and collagen is particularly important in the context of joint cartilage function and the treatment of joint diseases. Many factors affect the affinity of collagen for hyaluronan. One of the important factors is the ratio of 3- or 4-hydroxy proline to proline residues. This article presents the results from molecular dynamics calculations of HA-collagen type II interactions with hyaluronan. The applied protocol employed docking and geometry optimization of complexes built using collagen structures with different numbers of hydroxyl groups attached to proline moieties. It was established that the hydroxyproline/proline ratio affects both structural and energetic features of the collagen-hyaluronan complex. Proline hydroxylation was found to significantly influence the number of all identified types of molecular forces, hydrophobic interactions, water bridges and hydrogen bonds, which can be formed between collagen and hyaluronan. Importantly, an increase in the hydroxyproline/proline ratio in the collagen chain increases the binding affinity for hyaluronan. This is illustrated by the linear correlation between the binding free energy and the hydroxylation degree. A comparison of the results obtained for 3 and 4 hydroxylation of proline indicates that the hydroxyl group attachment position plays a minor role in complex stabilization. However, a slightly stronger affinity was observed for 4 hydroxylation. In order to evaluate the effect of the aqueous environment on the collagen-hyaluronan complex stability, the enthalpic and entropic contributions to the free energy of solvation were analyzed.

  • 106.
    Bhagavathiachari, Muthuraaman
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Elumalai, V.
    Gao, Jiajia
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Polymer-doped molten salt mixtures as a new concept for electrolyte systems in dye-sensitized solar cells2017In: ACS Omega, E-ISSN 2470-1343, Vol. 2, no 10, p. 6570-6575Article in journal (Refereed)
    Abstract [en]

    A conceptually new polymer electrolyte for dye-sensitized solar cells is reported and investigated. The benefits of using this type of electrolyte based on ionic liquid mixtures (ILMs) and room temperature ionic liquids are highlighted. Impedance spectroscopy and transient electron measurements have been used to elucidate the background of the photovoltaic performance. Even though larger recombination losses were noted, the high ion mobility and conductivity induced in the ILMs by the added polymer result in enhanced overall conversion efficiencies.

  • 107. Bhattacharya, Kunal
    et al.
    El-Sayed, Ramy
    Andon, Fernando T.
    Mukherjee, Sourav P.
    Gregory, Joshua
    Li, Hu
    Zhao, Yichen
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Seo, Wanji
    Fornara, Andrea
    Brandner, Birgit
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Leifer, Klaus
    Star, Alexander
    Fadeel, Bengt
    Lactoperoxidase-mediated degradation of single-walled carbon nanotubes in the presence of pulmonary surfactant (vol 91, pg 506, 2015)2015In: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 95, p. 766-766Article in journal (Refereed)
  • 108.
    Bhowmick, Asmit
    et al.
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Hussein, Rana
    Department of Biology, Humboldt Universität zu Berlin, Berlin, Germany.
    Bogacz, Isabel
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Simon, Philipp S.
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Ibrahim, Mohamed
    Department of Biology, Humboldt Universität zu Berlin, Berlin, Germany; Institute of Molecular Medicine, University of Lübeck, Lübeck, Germany.
    Chatterjee, Ruchira
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Doyle, Margaret D.
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Cheah, Mun Hon
    Molecular Biomimetics, Department of Chemistry — Ångström, Uppsala University, Uppsala, Sweden.
    Fransson, Thomas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Theoretical Chemistry and Biology.
    Chernev, Petko
    Molecular Biomimetics, Department of Chemistry — Ångström, Uppsala University, Uppsala, Sweden.
    Kim, In Sik
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Makita, Hiroki
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Dasgupta, Medhanjali
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Kaminsky, Corey J.
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Zhang, Miao
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Gätcke, Julia
    Department of Biology, Humboldt Universität zu Berlin, Berlin, Germany.
    Haupt, Stephanie
    Department of Biology, Humboldt Universität zu Berlin, Berlin, Germany.
    Nangca, Isabela I.
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Keable, Stephen M.
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Aydin, A. Orkun
    Molecular Biomimetics, Department of Chemistry — Ångström, Uppsala University, Uppsala, Sweden.
    Tono, Kensuke
    Japan Synchrotron Radiation Research Institute, Hyogo, Japan; RIKEN SPring-8 Center, Hyogo, Japan.
    Owada, Shigeki
    Japan Synchrotron Radiation Research Institute, Hyogo, Japan; RIKEN SPring-8 Center, Hyogo, Japan.
    Gee, Leland B.
    Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
    Fuller, Franklin D.
    Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
    Batyuk, Alexander
    Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
    Alonso-Mori, Roberto
    Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
    Holton, James M.
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA; Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA; SSRL, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
    Paley, Daniel W.
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Moriarty, Nigel W.
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Mamedov, Fikret
    Molecular Biomimetics, Department of Chemistry — Ångström, Uppsala University, Uppsala, Sweden.
    Adams, Paul D.
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA; Department of Bioengineering, University of California, Berkeley, CA, USA.
    Brewster, Aaron S.
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Dobbek, Holger
    Department of Biology, Humboldt Universität zu Berlin, Berlin, Germany.
    Sauter, Nicholas K.
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Bergmann, Uwe
    Department of Physics, University of Wisconsin–Madison, Madison, WI, USA.
    Zouni, Athina
    Department of Biology, Humboldt Universität zu Berlin, Berlin, Germany.
    Messinger, Johannes
    Molecular Biomimetics, Department of Chemistry — Ångström, Uppsala University, Uppsala, Sweden; Department of Chemistry, Umeå University, Umeå, Sweden.
    Kern, Jan
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Yano, Junko
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Yachandra, Vittal K.
    Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Structural evidence for intermediates during O2 formation in photosystem II2023In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 617, no 7961, p. 629-636Article in journal (Refereed)
    Abstract [en]

    In natural photosynthesis, the light-driven splitting of water into electrons, protons and molecular oxygen forms the first step of the solar-to-chemical energy conversion process. The reaction takes place in photosystem II, where the Mn4CaO5 cluster first stores four oxidizing equivalents, the S0 to S4 intermediate states in the Kok cycle, sequentially generated by photochemical charge separations in the reaction center and then catalyzes the O–O bond formation chemistry1–3. Here, we report room temperature snapshots by serial femtosecond X-ray crystallography to provide structural insights into the final reaction step of Kok’s photosynthetic water oxidation cycle, the S3→[S4]→S0 transition where O2 is formed and Kok’s water oxidation clock is reset. Our data reveal a complex sequence of events, which occur over micro- to milliseconds, comprising changes at the Mn4CaO5 cluster, its ligands and water pathways as well as controlled proton release through the hydrogen-bonding network of the Cl1 channel. Importantly, the extra O atom Ox, which was introduced as a bridging ligand between Ca and Mn1 during the S2→S3 transition4–6, disappears or relocates in parallel with Yz reduction starting at approximately 700 μs after the third flash. The onset of O2 evolution, as indicated by the shortening of the Mn1–Mn4 distance, occurs at around 1,200 μs, signifying the presence of a reduced intermediate, possibly a bound peroxide.

  • 109.
    Bian, Qingzhen
    et al.
    Linkoping Univ, Dept Phys Chem & Biol IFM, S-58183 Linkoping, Sweden..
    Ma, Fei
    Lund Univ, Div Chem Phys, S-22100 Lund, Sweden..
    Chen, Shula
    Linkoping Univ, Dept Phys Chem & Biol IFM, S-58183 Linkoping, Sweden..
    Wei, Qi
    Univ Macau, Inst Appl Phys & Mat Engn, Macau, Peoples R China..
    Su, Xiaojun
    Lund Univ, Div Chem Phys, S-22100 Lund, Sweden..
    Buyanova, Irina A.
    Linkoping Univ, Dept Phys Chem & Biol IFM, S-58183 Linkoping, Sweden..
    Chen, Weimin M.
    Linkoping Univ, Dept Phys Chem & Biol IFM, S-58183 Linkoping, Sweden..
    Ponseca, Carlito S.
    Linkoping Univ, Dept Phys Chem & Biol IFM, S-58183 Linkoping, Sweden..
    Linares, Mathieu
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Karki, Khadga J.
    Lund Univ, Div Chem Phys, S-22100 Lund, Sweden..
    Yartsev, Arkady
    Lund Univ, Div Chem Phys, S-22100 Lund, Sweden..
    Inganas, Olle
    Linkoping Univ, Dept Phys Chem & Biol IFM, S-58183 Linkoping, Sweden..
    Vibronic coherence contributes to photocurrent generation in organic semiconductor heterojunction diodes2020In: Nature Communications, E-ISSN 2041-1723, Vol. 11, no 1, article id 617Article in journal (Refereed)
    Abstract [en]

    Charge separation dynamics after the absorption of a photon is a fundamental process relevant both for photosynthetic reaction centers and artificial solar conversion devices. It has been proposed that quantum coherence plays a role in the formation of charge carriers in organic photovoltaics, but experimental proofs have been lacking. Here we report experimental evidence of coherence in the charge separation process in organic donor/acceptor heterojunctions, in the form of low frequency oscillatory signature in the kinetics of the transient absorption and nonlinear two-dimensional photocurrent spectroscopy. The coherence plays a decisive role in the initial 200 femtoseconds as we observe distinct experimental signatures of coherent photocurrent generation. This coherent process breaks the energy barrier limitation for charge formation, thus competing with excitation energy transfer. The physics may inspire the design of new photovoltaic materials with high device performance, which explore the quantum effects in the next-generation optoelectronic applications.

  • 110.
    Bijelic, Goran
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Shovsky, Alexander
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Varga, Imre
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Makuska, Ricardas
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry. KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Adsorption characteristics of brush polyelectrolytes on silicon oxynitride revealed by dual polarisation interferometry2010In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 348, p. 189-197Article in journal (Refereed)
    Abstract [en]

    Adsorption properties of bottle-brush polyelectrolytes have been investigated using dual polarization interferometry (DPI), which provides real time monitoring of adsorbed layer thickness and refractive index. The adsorption on silicon oxynitride was carried out from aqueous solution with no added inorganic salt, and the adsorbed polyelectrolyte layer was subsequently rinsed with NaCl solutions of increasing concentration. The bottle-brush polyelectrolytes investigated in this study have different ratios of permanent cationic charged segments and uncharged PEO side chains. Both the cationic groups and the PEO side chains have affinity for silica-like surfaces, and thus contribute to the adsorption process that becomes rather complex. Adsorption properties in water, responses to changes in ionic strength of the surrounding medium, adsorption kinetics and the layer structure are all strongly dependent on the ratio between backbone charges and side chains. The results are interpreted in terms of competitive adsorption of segments with different chemical nature. The adsorption kinetics is relatively fast, taking only tens to hundreds of seconds when adsorbed from dilute 100 ppm solutions. The DPI technique was found to be suitable for studying such rapid adsorption processes, including determination of the initial adsorption kinetics. We expect that the effects observed in this study are of general importance for synthetic and biological polymers carrying segments of different nature.

  • 111.
    Bin, Maddalena
    et al.
    Department of Physics, AlbaNova University Center, Stockholm University, 106 91 Stockholm, Sweden.
    Reiser, Mario
    Department of Physics, AlbaNova University Center, Stockholm University, 106 91 Stockholm, Sweden.
    Filianina, Mariia
    Department of Physics, AlbaNova University Center, Stockholm University, 106 91 Stockholm, Sweden.
    Berkowicz, Sharon
    Department of Physics, AlbaNova University Center, Stockholm University, 106 91 Stockholm, Sweden.
    Das, Sudipta
    Department of Physics, AlbaNova University Center, Stockholm University, 106 91 Stockholm, Sweden.
    Timmermann, Sonja
    Department Physik, Universität Siegen, Walter-Flex-Strasse 3, 57072 Siegen, Germany.
    Roseker, Wojciech
    Deutsches Elektronen-Synchrotron, Notkestrasse 85, 22607 Hamburg, Germany.
    Bauer, Robert
    Deutsches Elektronen-Synchrotron, Notkestrasse 85, 22607 Hamburg, Germany;Freiberg Water Research Center, Technische Universität Bergakademie Freiberg, 09599 Freiberg, Germany.
    Öström, Jonatan
    Department of Physics, AlbaNova University Center, Stockholm University, 106 91 Stockholm, Sweden.
    Karina, Aigerim
    Department of Physics, AlbaNova University Center, Stockholm University, 106 91 Stockholm, Sweden.
    Amann-Winkel, Katrin
    Department of Physics, AlbaNova University Center, Stockholm University, 106 91 Stockholm, Sweden;Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany;Institute of Physics, Johannes Gutenberg University, 55128 Mainz, Germany.
    Ladd-Parada, Marjorie
    Department of Physics, AlbaNova University Center, Stockholm University, 106 91 Stockholm, Sweden.
    Westermeier, Fabian
    Deutsches Elektronen-Synchrotron, Notkestrasse 85, 22607 Hamburg, Germany.
    Sprung, Michael
    Deutsches Elektronen-Synchrotron, Notkestrasse 85, 22607 Hamburg, Germany.
    Möller, Johannes
    European X-Ray Free-Electron Laser Facility, Holzkoppel 4, 22869 Schenefeld, Germany.
    Lehmkühler, Felix
    Deutsches Elektronen-Synchrotron, Notkestrasse 85, 22607 Hamburg, Germany;The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany.
    Gutt, Christian
    Department Physik, Universität Siegen, Walter-Flex-Strasse 3, 57072 Siegen, Germany.
    Perakis, Fivos
    Department of Physics, AlbaNova University Center, Stockholm University, 106 91 Stockholm, Sweden.
    Coherent X-ray Scattering Reveals Nanoscale Fluctuations in Hydrated Proteins2023In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 127, no 21, p. 4922-4930Article in journal (Refereed)
    Abstract [en]

    Hydrated proteins undergo a transition in the deeply supercooled regime, which is attributed to rapid changes in hydration water and protein structural dynamics. Here, we investigate the nanoscale stress-relaxation in hydrated lysozyme proteins stimulated and probed by X-ray Photon Correlation Spectroscopy (XPCS). This approach allows us to access the nanoscale dynamics in the deeply supercooled regime (T = 180 K), which is typically not accessible through equilibrium methods. The observed stimulated dynamic response is attributed to collective stress-relaxation as the system transitions from a jammed granular state to an elastically driven regime. The relaxation time constants exhibit Arrhenius temperature dependence upon cooling with a minimum in the Kohlrausch-Williams-Watts exponent at T = 227 K. The observed minimum is attributed to an increase in dynamical heterogeneity, which coincides with enhanced fluctuations observed in the two-time correlation functions and a maximum in the dynamic susceptibility quantified by the normalized variance χT. The amplification of fluctuations is consistent with previous studies of hydrated proteins, which indicate the key role of density and enthalpy fluctuations in hydration water. Our study provides new insights into X-ray stimulated stress-relaxation and the underlying mechanisms behind spatiotemporal fluctuations in biological granular materials.

  • 112.
    Birgersson, Henrik
    et al.
    KTH, Superseded Departments (pre-2005), Chemical Engineering and Technology.
    Boutonnet, Magali
    KTH, Superseded Departments (pre-2005), Chemical Engineering and Technology.
    Järås, Sven G.
    KTH, Superseded Departments (pre-2005), Chemical Engineering and Technology.
    Eriksson, L.
    Deactivation and regeneration of spent three-way automotive exhaust gas catalysts (TWC)2004In: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 30-1, no 1-4, p. 433-437Article in journal (Refereed)
    Abstract [en]

    The effect of oxidation, oxy-chlorination and reduction treatments at elevated temperatures on the dispersion of palladium (Pd) and rhodium (Rh) for commercially aged three-way automotive exhaust gas catalysts (TWC) has been investigated. The catalytic activity of treated samples was compared with a reference sample, which was taken from the corresponding aged TWC and tested using a 'mini-cuts' reactor simulating real driving conditions. In the case of oxygen, the improvement of the noble metal dispersion on the catalysts was dependent on the noble metal loading and the degree of metal sintering. Adding chlorine to the oxygen atmosphere facilitates the restructuring of the metals with an improved increase in the noble metal dispersion. The temperature and the composition of the gas used during these thermal treatments proved to be of importance not only to increase the metal dispersion, but also to prevent possible losses of noble metals, in the form of volatile MOxCly compounds. TEM-EDS techniques indicated changes in the size of the largest noble metal agglomerates of Lip to 100 nm in size after thermal gas treatment. BET porosity and XRD analyses were employed to investigate restructuring of the washcoat and showed a decrease in pore size distribution and an increase in surface area.

  • 113. Birsoz, B.
    et al.
    Baykal, A.
    Sozeri, H.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Synthesis and characterization of polypyrrole-BaFe12O19 nanocomposite2010In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 493, no 1-2, p. 481-485Article in journal (Refereed)
    Abstract [en]

    Polypyrrole-BaFe12O19 nanocomposite was successfully synthesized by an in situ polymerization of pyyrole in the presence of synthesized BaFe12O19 nanoparticles. Structural, morphological, electrical and magnetic properties of the nanocomposite were performed by XRD, FT-IR, TEM, TGA, VSM and ac conductivity measurements respectively. XRD analysis reveals the inorganic phase as bariumhexaferrite and TGA shows about 22 wt% loading of hexaferrite in the nanocomposite. FT-IR analysis indicates a successful conjugation of hexaferrite particles with polypyrrole. Magnetization measurements show that polypyrrole coating decreases the saturation magnetization of BaFe12O19 significantly. This reduction has been explained by the pinning of the surface spins by the possible adsorption of non-magnetic ions during the polymerization process. Interactions between the hard and impurity phases, determined using the Stoner-Wohlfarth theory, reveal that particles' single domain character and the coating destabilizes the remanence state of the polypyrrole-BaFe12O19 nanocomposite.

  • 114.
    Bjorkbacka, Asa
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Johnson, C. Magnus
    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.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Role of the Oxide Layer in Radiation-Induced Corrosion of Copper in Anoxic Water2016In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 120, no 21, p. 11450-11455Article in journal (Refereed)
    Abstract [en]

    The influence of a pregrown copper oxide layer on radiation-induced corrosion of polished copper in pure anoxic water has been explored. The resulting amount of copper oxide formed during corrosion was measured with cathodic reduction, and the concentration of dissolved copper in solution was measured with inductively coupled plasma atomic emission spectroscopy. The identity of corrosion products and their topography was determined with Raman spectroscopy and scanning electron microscopy, respectively. Nonirradiated reference samples were analyzed for comparison. The results show that radiation-induced corrosion of copper in anoxic water is significantly more effective on preoxidized copper compared to polished copper. The total amount of oxidized copper exceeds the amount expected solely from radiation chemistry of water by more than 3 orders of magnitude. To explain this discrepancy a mechanism is suggested where the hydroxyl radical (HO center dot) is the main radiolytic oxidative species driving the corrosion process. If the thermodynamic driving force would be large enough (such as for the hydroxyl radical or its precursor, H2O+), the oxide layer could conduct electrons from the metal to the hydroxyl radicals formed at oxide surfaces. The formation of an oxide layer will then result in an increased reactive surface area partly accounting for the observed discrepancy.

  • 115.
    Björkbacka, Åsa
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Radiation induced corrosion of copper2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The process of radiation induced corrosion of copper is not well understood. The most obvious situation where the knowledge of this process is crucial is in a deep repository for high level spent nuclear fuel where the fuel will be sealed inside copper canisters. The radiation will penetrate the canisters and be absorbed by the surrounding environment. In this study gamma irradiations of polished and pre-oxidized copper cubes in anoxic pure water, air of 60-100 % RH and in humid argon were performed. The copper surfaces were examined using IRAS, XPS, cathodic reduction, SEM, AFM, and Raman spectroscopy. The concentration of copper in the reaction solutions was measured using ICP-OES.  Also the formation of oxidative species caused by radiation absorption of water was studied by numerical simulations using MAKSIMA software. The corrosion of copper during gamma irradiation vastly exceeds what is expected. The production of oxidative species caused by radiation absorption of water is hundreds of times too low to explain the amount of oxidized copper. A possible explanation for this mismatch is an enhanced radiation chemical yield of HO· on the copper surface. Another one is an increased surface area due to oxidation of copper. One speculation is that HO· interacting with the copper oxide can cause oxidation of the metal. If the thermodynamic driving force is large enough then electrons can be conducted from the metal through the oxide to the oxidant. A dramatic increase in surface area together with an increased interfacial yield of HO· might explain the radiation enhanced corrosion process.   

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    Thesis
  • 116.
    Blad, Amanda
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Glisén, Helena
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Ludvig, Filippa
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Photochemistry of Copper Coordination Complexes2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The United Nations have set a number of sustainability goals, Agenda 2030, in order to combat the worlds largest challenges and injustices. The energy market is one of these urgent issues which must be solved. Solar energy is expected to be the fastest growing energy source in the future energy mix. It can be a great way to provide zero emission energy and also become a key part in equality as it can provide energy to people who live off the grid today and raise quality of life all over the world. The aim of this study is to compare different ligands in a copper halide complex to conclude what structural properties of the ligand might be better suited for photoluminescent applications, and especially in solar cells. Eight ligands were chosen for the complexes depending on their level of conjugation: 4,4’-bipyridine, tri(o-tolyl)phosphine, 3,6-di-2-pyridyl-1,2,4,5-tetrazine, pyridine, pyrimidine, pyrazine, phenanthroline, and 2,2’-bipyridine. A series of analytical methods were used to compare the complexes properties; X-Ray diffraction, emission and excitation spectroscopy, time-resolved photoluminescence spectroscopy, microscopy and thermochromism. From these measurements, pyridine and pyrimidine proved to have the greatest potential for working in a solar cell. This was deduced because of the detected crystallinity, having luminescence under UV-light, forming distinct wavelength peaks during excitation and emission in the flourometer, having the longest excited state lifetime and and finally, emitting distinctive colours during thermochromism. When creating the solar cell, pyridine was chosen as ligand due to higher availability than pyrimidine. The method used in this project for making the solar cell is directly applied form a previously tested method, but which was designed for another type of electron donor. This project compared the different ways of applying the copper halide complex on to the cell. The methods used were spin-coating and SILAR for creating the copper iodide thin film and vapour diffusion and immersion to introduce the ligand. These four methods were combined systematically for all combinations. The solar cells were then put in a solar simulator where voltage, current, efficiency and fill factor was measured. The best results came form the solar cell where spin coating and immersion was used, though the overall efficiency of the created cells were low. Copper halide complexes in previous studies have been proven to be reactive with oxygen and the experiments in this project were not carried out in an inert environment. This could have had significant impact on the measurements, as reactions between the complexes and oxygen may have resulted in oxidation and thus inactivation of the complexes. Therefore, it would be interesting to conduct the syntheses again but instead in an inert environment to determine whether oxygen made a major impact on the measurements. In further studies, it would also be worthwhile to investigate how the different layers of the solar cell would have to be adapted for this particular complex to obtain higher efficiency and voltage. Also, making thin film of pyrimidine to be used in a solar cell as it showed the attributes required for a solar cell. Furthermore, it would be interesting to use derivatives of pyrimidine, such as uracil and cytosine which are abundant in nature, as they might be more sustainable choices. This is due to their inherent biodegradability and not posing a threat to either health or environment when handled.

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  • 117. Bleskov, I. D.
    et al.
    Smirnova, E. A.
    Vekilov, Y. K.
    Korzhavyi, Pavel A.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Johansson, Börje
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Katsnelson, M.
    Vitos, Levente
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Abrikosov, I. A.
    Isaev, E. I.
    Ab initio calculations of elastic properties of Ru1-xNixAl superalloys2009In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 94, no 16Article in journal (Refereed)
    Abstract [en]

    Ab initio total energy calculations based on the exact muffin-tin orbitals method, combined with the coherent potential approximation, have been used to study the thermodynamical and elastic properties of substitutional refractory Ru1-xNixAl alloys. We have found that the elastic constants C' and C11 exhibit pronounced peculiarities near the concentration of about 40 at. % Ni, which we ascribe to electronic topological transitions. Our suggestion is supported by the Fermi surface calculations in the whole concentration range. Results of our calculations show that one can design Ru-Ni-Al alloys substituting Ru by Ni (up to 40 at. %) with almost invariable elastic constants and reduced density.

  • 118.
    Blom, Hans
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Experimental Biomolecular Physics.
    Chmyrov, Andriy
    KTH, School of Engineering Sciences (SCI), Applied Physics, Experimental Biomolecular Physics.
    Hassler, Kai
    KTH, School of Engineering Sciences (SCI), Applied Physics, Experimental Biomolecular Physics.
    Davis, L.M.
    Widengren, Jerker
    KTH, School of Engineering Sciences (SCI), Applied Physics, Experimental Biomolecular Physics.
    Triplet-State Investigations of Fluorescent Dyes at Dielectric Interfaces Using Total Internal Reflection Fluorescence Correlation Spectroscopy2009In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 113, no 19, p. 5554-5566Article in journal (Refereed)
    Abstract [en]

    The triplet-state kinetics of several fluorescent dyes used in ultrasensitive fluorescence microscopy are investigated using total internal reflection fluorescence correlation spectroscopy (TIR-FCS). A theoretical outline of the correlation analysis and the physical aspects of evanescent excitation and fluorescence emission at dielectric interfaces are given. From this analysis, the rates of intersystem crossing and triplet decay are deduced for fluorescein, ATTO 488, rhodamine 110, rhodamine 123, and rhodamine 6G in aqueous buffer solutions. All investigated dyes show slightly higher triplet rates at the dielectric interface compared to bulk solution measurements. We attribute this enhancement to possible modifications of the dyes’ photophysical properties near a dielectric interface. In the case of rhodamine 6G, the impact of changes in the dye concentration, ionic strength of the solvent, and potassium iodide concentration are also investigated. This leads to a better understanding of the influences of dye−dye, dye−solvent, and dye−surface interactions on the increased triplet intersystem crossing and triplet decay rates. The study shows that analysis of triplet-state kinetics by TIR-FCS not only results in a better understanding of how the photophysical properties of the dyes are affected by the presence of an interface, but also provides a means for probing the microenvironment near dielectric interfaces.

  • 119.
    Blom, Hans
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Experimental Biomolecular Physics.
    Hassler, Kai
    KTH, School of Engineering Sciences (SCI), Applied Physics, Experimental Biomolecular Physics.
    Chmyrov, Andriy
    KTH, School of Engineering Sciences (SCI), Applied Physics, Experimental Biomolecular Physics.
    Widengren, Jerker
    KTH, School of Engineering Sciences (SCI), Applied Physics, Experimental Biomolecular Physics.
    Electrostatic Interactions of Fluorescent Molecules with Dielectric Interfaces Studied by Total Internal Reflection Fluorescence Correlation Spectroscopy2010In: International Journal of Molecular Sciences, ISSN 1661-6596, E-ISSN 1422-0067, Vol. 11, no 2, p. 368-406Article in journal (Refereed)
    Abstract [en]

    Electrostatic interactions between dielectric surfaces and different fluorophoresused in ultrasensitive fluorescence microscopy are investigated using objective-based TotalInternal Reflection Fluorescence Correlation Spectroscopy (TIR-FCS). The interfacialdynamics of cationic rhodamine 123 and rhodamine 6G, anionic/dianionic fluorescein,zwitterionic rhodamine 110 and neutral ATTO 488 are monitored at various ionic strengthsat physiological pH. As analyzed by means of the amplitude and time-evolution of theautocorrelation function, the fluorescent molecules experience electrostatic attraction orrepulsion at the glass surface depending on their charges. Influences of the electrostaticinteractions are also monitored through the triplet-state population and triplet relaxationtime, including the amount of detected fluorescence or the count-rate-per-moleculeparameter. These TIR-FCS results provide an increased understanding of how fluorophoresare influenced by the microenvironment of a glass surface, and show a promising approachfor characterizing electrostatic interactions at interfaces.

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    AndriyChmyrov-IntJMolSci2010
  • 120.
    Blomberg, Eva
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Claesson, Per Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Konradsson, Peter
    Department of Physics, Chemistry and Biology, Linköping University.
    Liedberg, Bo
    Department of Physics, Chemistry and Biology, Linköping University.
    Globotriose- and oligo(ethylene glycol)-terminated self-assembled monolayers: Surface forces, wetting, and surfactant adsorption2006In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 22, no 24, p. 10038-10046Article in journal (Refereed)
    Abstract [en]

    A set of oligo( ethylene glycol)-terminated and globotriose-terminated self-assembled monolayers (SAMs) has been prepared on gold substrates. Such model surfaces are well defined and have good stability due to the strong binding of thiols and disulfides to the gold substrate. They are thus very suitable for addressing questions related to effects of surface composition on wetting properties, surface interactions, and surfactant adsorption. These issues are addressed in this report. Accurate wetting tension measurements have been performed as a function of temperature using the Wilhelmy plate technique. The results show that the nonpolar character of oligo( ethylene glycol)-terminated SAMs increases slightly but significantly with temperature in the range 20-55 degrees C. On the other hand, globotriose-terminated SAMs are fully wetted by water at room temperature. Surface forces measurements have been performed and demonstrated that the interactions between oligo( ethylene glycol)-terminated SAMs are purely repulsive and similar to those determined between adsorbed surfactant layers with the same terminal headgroup. On the other hand, the interactions between globotriose-terminated SAMs include a short-range attractive force component that is strongly affected by the packing density in the layer. In some cases it is found that the attractive force component increases with contact time. Both these observations are rationalized by an orientation- and conformation-dependent interaction between globotriose headgroups, and it is suggested that hydrogen-bond formation, directly or via bridging water molecules, is the molecular origin of these effects.

  • 121.
    Blomberg, Eva
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Kumpulainen, Atte
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    David, C.
    Laboratoire de Recherche sur les Polymères, CNRS, Thiais, France.
    Amiel, C.
    Laboratoire de Recherche sur les Polymères, CNRS, Thiais, France.
    Polymer bilayer formation due to specific interactions between beta-cyclodextrin and adamantane: A surface force study2004In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 20, no 24, p. 10449-10454Article in journal (Refereed)
    Abstract [en]

    The purposes of this study are to utilize the interactions between an adamantane end-capped poly(ethylene oxide) (PEO) and a cationic polymer of beta-cyclodextrin to build polymer bilayers on negatively charged surfaces, and to investigate the interactions between such layers. The association of this system in solution has been studied by rheology, light scattering, and fluorescence measurements. It was found that the adamantane-terminated PEO (PEC-Ad) mixed with the beta-cyclodextrin polymer gives complexes where the interpolymer links are formed by specific inclusion of the adamantane groups in the beta-cyclodextrin cavities. This results in a higher viscosity of the solution and growth of intermolecular clusters. The interactions between surfaces coated with a cationized beta-cyclodextrin polymer across a water solution containing PEO-Ad polymers were studied by employing the interferometric surface force apparatus (SFA). In the first step, the interaction between mica surfaces coated with the cationized beta-cyclodextrin polymer in pure water was investigated. It was found that the beta-cyclodextrin polymer adsorbs onto mica and almost neutralizes the surface charge. The adsorbed layers of the beta-cyclodextrin polymer are rather compact, with a layer thickness of about 60 Angstrom (30 Angstrom per surface). Upon separation, a very weak attractive force is observed. The beta-cyclodextrin solution was then diluted by pure water by a factor of 3000 and a PEO-Ad polymer was introduced into the solution. Two different architectures of the PEO-Ad polymer were investigated: a four-arm structure and a linear structure. After the adsorption of the PEO polymer onto the beta-cyclodextrin layer reached equilibrium, the forces were measured again. It was found that the weak repulsive long-range force had disappeared and an attractive force caused the surfaces to jump into contact, and that the compressed layer thickness had increased. The attractive force is interpreted as being due to a specific recognition between the hydrophobic adamantane groups on the PEO-Ad polymer and the hydrophobic cavity in the beta-cyclodextrin molecules. Furthermore, the attractive force observed on separation has increased significantly, which is a further indication of a specific interaction between the beta-cyclodextrin polymer and the adamantane groups.

  • 122.
    Blomberg, Eva
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Lundin, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Layer-by-Layer Assembly of Biomacromolecules2011In: Encyclopedia of Surface and Colloid Science, SecondEdition / [ed] P. Somasundaran, London: Taylor & Francis, 2011, 1, p. 1-14Chapter in book (Refereed)
    Abstract [en]

    The ability to construct thin films with controlled thickness on almost any type of surface is of great interestin many research fields. For biomedical applications, thin films on medical devices have been found toimprove the biocompatibility, reduce the immunological response, and deliver medical drugs locally. Thelayer structure is closely related to the function and efficiency of such films. During the last decades, it hasbeen shown that the layer-by-layer (LbL) assembly of charged macromolecules has created an inexpensiveroute to the formation of thin multilayer films, and the interest in using biomacromolecules (e.g., polysaccharidesand proteins) has emerged in recent years. The LbL technique offers unique opportunities forcontrolling the physical properties of thin surface layers, such as film thickness, chemical and elasticproperties, and stability. In this entry, we will focus on recent advances in the multilayer film area usingbiomacromolecules. We will discuss how different physicochemical properties of biomacromolecules andof the deposition solution affect the formation and structure of LbL-assembled multilayer. Finally, we willaddress some suggested applications for these biopolymer film coatings.

  • 123.
    Blomberg, Eva
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Poptoshev, Evgeni
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Caruso, F.
    Centre for Nanoscience and Nanotechnology, Department of Chemical and Biomolecular Engineering, University of Melbourne, Victoria, Australia.
    Surface interactions during polyelectrolyte multilayer build-up. 2. The effect of ionic strength on the structure of preformed multilayers2006In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 22, no 9, p. 4153-4157Article in journal (Refereed)
    Abstract [en]

    Interactions between surfaces bearing multilayer films of poly(allylamine hydrochloride) (PAH) and poly(styrenesulfonate sodium salt) (PSS) were investigated across a range of aqueous KBr solutions. Three layer films (PAH/PSS/PAH) were preassembled on mica surfaces, and the resulting interactions were measured with the interferometric surface force apparatus (SFA). Increasing the ionic strength of the medium resulted in a progressive swelling of the multilayer films. Interactions in solutions containing more than 10(-3) M KBr were dominated by a long-ranged steric repulsion originating from compression of polyelectrolyte segments extending into solution. In 10(-1) M KBr, repeated measurements at the same contact position showed a considerable reduction of the range and the strength of the steric force, indicating a flattening of the film during initial approach. Furthermore, this flattening was irreversible on the time scale of the experiments, and measurements performed up to 72 h after the initial compression showed no signs of relaxation. These studies aid in understanding the dominant interactions between polyelectrolyte multilayers, including polyelectrolyte films deposited on colloidal particles, which is important for the preparation of colloidally stable nanoengineered particles.

  • 124.
    Blomberg, Eva
    et al.
    KTH, Superseded Departments (pre-2005), Chemistry.
    Poptoshev, Evgeni
    KTH, Superseded Departments (pre-2005), Chemistry.
    Claesson, Per M.
    KTH, Superseded Departments (pre-2005), Chemistry.
    Caruso, F.
    Centre for Nanoscience and Nanotechnology, Department of Chemical and Biomolecular Engineering, The University of Melbourne, Victoria, Australia.
    Surface interactions during polyelectrolyte multilayer buildup. 1. Interactions and layer structure in dilute electrolyte solutions2004In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 20, no 13, p. 5432-5438Article in journal (Refereed)
    Abstract [en]

    We report the investigation of surface forces between polyelectrolyte multilayers of poly(allylamine hydrochloride) (PAH) and poly(styrenesulfonate sodium salt) (PSS) assembled on mica surfaces during film buildup using a surface force apparatus. Up to four polyelectrolyte layers were prepared on each surface ex situ, and the surface interactions were measured in 10(-4) M KBr solutions. The film thickness under high compressive loads (above 2000 muN/m) increased linearly with the number of deposited layers. In all cases, the interaction between identical surfaces at large separations (> 100 Angstrom from contact) was dominated by electrostatic double-layer repulsion. By fitting DLVO theory to the experimental force curves, the apparent double-layer potential of the interacting surfaces was calculated. At shorter separations, an additional non-DLVO repulsion was present due to polyelectrolyte chains extending some distance from the surface into solution, thus generating an electrosteric type of repulsion. Forces between dissimilar multilayers (i.e., one of the multilayers terminated with PSS and the other with PAH) were attractive at large separations (30-400 Angstrom) owing to a combination of electrostatic attraction and polyelectrolyte bridging.

  • 125.
    Blomberg, Eva
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Verrall, Ronald
    Department of Chemistry, University of Saskatchewan, Saskatoon, Canada.
    Claesson, Per M
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Interactions between adsorbed layers of cationic gemini surfactants2008In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 24, no 4, p. 1133-1140Article in journal (Refereed)
    Abstract [en]

    The forces acting between glass and between mica surfaces in the presence of two cationic gemini surfactants, 1,4 diDDAB (1,4-butyl-bis(dimethyldodecylammonium bromide)) and 1,12 diDDAB (1,12-dodecyl-bis(dimethyldodecylammonium bromide)), have been investigated below the critical micelle concentration (cmc) of the surfactants using two different surface force techniques. In both cases, it was found that a recharging of the surfaces occurred at a surfactant concentration of about 0.1 x cmc, and at all surfactant concentrations investigated repulsive double-layer forces dominated the interaction at large separations. At smaller separations, attractive forces, or regions of separation with (close to) constant force, were observed. This was interpreted as being due to desorption and rearrangement in the adsorbed layer induced by the proximity of a second surface. Analysis of the decay length of the repulsive double-layer force showed that the majority of the gemini surfactants were fully dissociated. However, the degree of ion pair formation, between a gemini surfactant and a bromide counterion, increased with increasing surfactant concentration and was larger for the gemini surfactant with a shorter spacer length.

  • 126.
    Blomdahl, Emil
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Synthesis and characterization of novel hybrid organic-inorganic materials2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The demand for better and more sustainable material is increasing. More efficient materials will be needed to meet the growing global need. Hybrid organic-inorganic materials are one type of materials that have been of great interest recently, which can be described as a class of materials that mix organic and inorganic components. This thesis focused on hybrid organic-inorganic materials inspired by the classical perovskite crystal structure ABX3, where component A is an organic cation, component B is a divalent metal cation and component X is an anion. Hybrid organic-inorganic materials based on the classical perovskite structure may have various functional properties and may have a broad range of potential applications. Some examples of those properties as well as some and possible applications include good photoconductivity and power conversion efficiency for photovoltaic devices, excellent emission properties for light emitting diodes and tunable dielectric properties for electronic switches and sensors. 

    The physical properties of the hybrid organic-inorganic material are determined by the crystal structure of the material, which in turn will be decided by the choice of components. With the many possible choices for organic and inorganic components, there is an opportunity to synthesize completely new hybrid organic-inorganic compounds that may display new or superior physical properties.

    Current hybrid organic-inorganic materials based on the perovskite crystal structure mainly use lead as the divalent metal, since it currently gives the best performance. The toxicity of lead is a major drawback for current lead-based hybrid organic-inorganic materials. The possibility to replace lead with another divalent metal has been explored during this project. For this thesis, the organic cation cyclohexylammonium (CHA) has been of focus as the organic component.

    The aim of this thesis was to design, synthesize and characterize novel hybrid organic-inorganic compounds. The hybrid organic-inorganic compounds CHAZnBr3 and (CHA)2ZnBr4 were synthesized for the first time, to the best of our knowledge, and will be the focus of this thesis. The two new hybrid organic-inorganic compounds were structurally characterized by X-ray Diffraction (XRD) and thermally characterized by Thermal Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). 

    The first compound, CHAZnBr3, could be determined to be orthorhombic at 298 K. The compound was found to be thermally stable up 490 K, and to undergo a phase transition at 445 K.  The second compound, (CHA)2ZnBr4, could not be fully structurally solved at either 100 K or 298 K. The compound was found to be thermally stable up to 490 K, and to undergo a phase transition at 230 K.  Further characterization will be needed to better understand the properties of these two compounds and their possible applications.

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  • 127.
    Blomdahl, Kajsa-My
    KTH, School of Chemical Science and Engineering (CHE).
    Numerical Calculations of Efimov States in Ultracold Atomic Systems2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In systems of ultracold atoms,  the  quantum  Efimov  effect  can  appear where identical bosons form an infinite tower of bound trimer states in the resonant limit, at the bound dimer dissociation threshold. The most characteristic feature of this effect is that their energy spectrum obey a geometric scaling law, which is universal in the sense that it emerges irrespective of the nature of the two body forces. Using  a  model  potential,  constructed  to  resemble the two body interaction between alkali atoms,  which was  fine tuned to control the  scattering  length,  energy  eigenvalues  for  the  two-  and  threebody problem were calculated numerically. The results where  fitted  to  the analytic theory and the appearance of the first Efimov state was positioned at a scattering length of -9.23rvdW , which is in good  agreement  with  the universal value -9.2rvdW .

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  • 128.
    Bodvik, Rasmus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Bulk and interfacial properties of cellulose ethers2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This work summarizes several studies that all concern cellulose ethers of the types methylcellulose (MC) hydroxypropylmethylcellulose (HPMC) and ethyl(hydroxyethyl)cellulose (EHEC). They share the feature of negative temperature response, as they are soluble in water at room temperature but phase separate and sometimes form gels at high temperatures. The different types of viscosity transitions occurring in these three cellulose ethers are well-known. However, earlier studies have not solved the problem of why both HPMC and EHEC, as the temperature increases, exhibit a viscosity decrease just before the viscosity increases, whereas MC only has one transition temperature where the viscosity increases. With our investigations we have aimed to compare the effect of temperature on bulk solutions and on adsorbed layers of the different polymers using a range of techniques.

    Light scattering and cryo transmission electron microscopy (cryo-TEM) was employed to study aggregation of MC, HPMC and EHEC in solution. The solvent quality of water is reduced for all three polymers in solution as the temperature increases, and this infers an onset of aggregation at a certain temperature. The aggregation rate follows the order EHEC > HPMC > MC. Cryo-TEM pictures of solutions frozen from high temperatures showed closely packed fibrils forming dense networks in MC solution. Some fibrils were also found in HPMC solution above the transition temperature, but they did not interconnect readily. This is explained by the bulky and hydrophilic hydroxypropyl groups attached to HPMC. EHEC has similar substituents, while MC only has short and hydrophobic methyl groups attached to the main chain.

    An amphiphilic liquid, diethyleneglycolmonobutylether (BDG) was used as an additive to change the properties of MC solutions in water. With 10 wt% BDG added, the effect was similar in viscosity and light scattering measurements as well as cryo-TEM pictures, inducing a temperature response resembling that of HPMC in pure water. 5 wt% of BDG was enough to change the aggregation type and induce a transition temperature with viscosity decrease. The effect of the additive is rationalized by BDG acting as a hydrophobic and bulky substituent in MC, similar to the large substituents in HPMC and EHEC.

    Two instruments, a quartz crystal microbalance with dissipation (QCM-D) and an ellipsometer, were used in parallel to determine the changes with temperature on an adsorbed layer of MC and HPMC on silica kept in water and in polymer solution. The silica needed to be hydrophobized for significant adsorption to take place. Adsorption was similar for both polymers at low temperatures, whereas a sharp transition in several layer properties occurred for HPMC, but not for MC, close to the solution viscosity transition temperature. Atomic force microscopy (AFM) was used to measure attractive and repulsive forces and also friction forces between MC layers in polymer solution. The small changes in normal forces with temperature infer that the hydrophobic groups in MC are mostly depleted from the surface. The surface–polymer interactions increase with increasing temperature and the layer becomes more cohesive, which induces a higher load bearing capacity and lower friction when measured at high loads. AFM imaging was employed to obtain the height distribution in MC adsorbed layers. These images indicate that fibril-like structures were formed at a lower temperature in the surface layer than in bulk solution.

    The different preferences for adsorption and for aggregation in MC and HPMC above the solution transition temperatures are explained by the fibril formation in MC shielding hydrophobic parts of the polymer from the solution, and thus counteracting adsorption, but also fast aggregation. The viscosity decrease in HPMC and EHEC is conferred to intra-chain contraction and aggregation into less extended structures.

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  • 129.
    Bodvik, Rasmus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Dédinaité, Andra
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Karlson, Leif
    Bergström, Lars Magnus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Baverback, Petra
    Pedersen, Jan Skov
    Edward, Katarina
    Karlsson, Göran
    Varga, Imre
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Aggregation and network formation of aqueous methylcellulose and hydroxypropylmethylcellulose solutions2010In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, E-ISSN 1873-4359, Vol. 354, no 1-3, p. 162-171Article in journal (Refereed)
    Abstract [en]

    Solution properties of methylcellulose (MC) and hydroxypropylmethylcellulose (HPMC) have been investigated as a function of temperature and concentration using a broad range of experimental techniques. Novelties include the extensive comparison between MC and HPMC solutions as well as the combination of techniques, and the use of Cryo transmission electron microscopy (Cryo-TEM). The correlation between rheology and light scattering results clearly demonstrates the relation between viscosity change and aggregation. Cryo-TEM images show the network structures formed. Viscosity measurements show that for both MC and HPMC solutions sudden changes in viscosity occur as the temperature is increased. The onset temperature for these changes depends on polymer concentration and heating rate. For both MC and HPMC solutions the viscosity on cooling is very different compared to on heating, demonstrating the slow equilibration time. The viscosity changes in MC and HPMC solutions are dramatically different; for MC solutions the viscosity increases by several orders of magnitude when a critical temperature is reached, whereas for HPMC solutions the viscosity decreases abruptly at a given temperature, followed by an increase upon further heating. Light and (SAXS) small-angle X-ray scattering shows that the increase in viscosity, for MC as well as for HPMC solutions, is due to extensive aggregation of the polymers. Light scattering also provides information on aggregation kinetics. The SAXS measurements allow us to correlate aggregation hysteresis to the viscosity hysteresis, as well as to extract some structural information. Cryo-TEM images give novel information that a fibrillar network is formed in MC solutions, and the strong viscosity increase occurs when this network spans the whole solution volume. For HPMC solutions the behaviour is more complex. The decrease in viscosity can be related to the formation of compact objects, and the subsequent increase to formation of fibrillar structures, which are more linear and less entangled than for MC.

  • 130.
    Bodvik, Rasmus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Karlson, Leif
    Edwards, Katarina
    Eriksson, Jonny
    Thormann, Esben
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Aggregation of Modified Celluloses in Aqueous Solution: Transition from Methylcellulose to Hydroxypropylmethylcellulose Solution Properties Induced by a Low-Molecular-Weight Oxyethylene Additive2012In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 28, no 38, p. 13562-13569Article in journal (Refereed)
    Abstract [en]

    Temperature effects on the viscosity and aggregation behavior of aqueous solutions of three different cellulose ethers-methylcellulose (MC), hydroxypropylmethylcellulose (HPMC), and ethyl(hydroxyethyl)cellulose (EHEC)-were investigated using viscosity and dynamic light scattering measurements as well as cryo-TEM. In all cases, increasing temperature reduces the solvent quality of water, which induces aggregation. It was found that the aggregation rate followed the order EHEC > HPMC > MC, suggesting that cellulose ethers containing some bulky and partially hydrophilic substituents assemble into large aggregates more readly than methylcellulose. This finding is discussed in terms of the organization of the structures formed by the different cellulose ethers. The temperature-dependent association behavior of cellulose ethers was also investigated in a novel way by adding diethyleneglycolmonobutylether (BDG) to methylcellulose aqueous solutions. When the concentration of BDG was at and above 5 wt %, methylcellulose adopted HPMC-like solution behavior. In particular, a transition temperature where the viscosity was decreasing, prior to increasing at higher temperatures, appeared, and the aggregation rate increased. This observation is rationalized by the ability of amphiphilic BDG to accumulate at nonpolar interfaces and thus also to associate with hydrophobic regions of methylcellulose. In effect, BDG is suggested to act as a physisorbed hydrophilic and bulky substituent inducing constraints on aggregation similar to those of the chemically attached hydroxypropyl groups in HPMC and oligo(ethyleneoxide) chains in EHEC.

  • 131.
    Bodvik, Rasmus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Macakova, Lubica
    Karlson, Leif
    Thormann, Esben
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Temperature-Dependent Competition between Adsorption and Aggregation of a Cellulose Ether-Simultaneous Use of Optical and Acoustical Techniques for Investigating Surface Properties2012In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 28, no 25, p. 9515-9525Article in journal (Refereed)
    Abstract [en]

    Adsorption of the temperature-responsive polymer hydroxypropylmethylcellulose (HPMC) from an aqueous solution onto hydrophobized silica was followed well above the bulk instability temperature (T-2) in temperature cycle experiments. Two complementary techniques, QCM-D and ellipsometry, were utilized simultaneously to probe the same substrate immersed in polymer solution. The interfacial processes were correlated with changes in polymer aggregation and viscosity of polymer solutions, as monitored by light scattering and rheological measurements. The simultaneous use of ellipsometry and QCM-D, and the possibility to follow layer properties up to 80 degrees C, well above the T-2 temperature, are both novel developments. A moderate increase in adsorbed amount with temperature was found below T-2, whereas a significant increase in the adsorbed mass and changes in layer properties were observed around the T-2 temperature where the bulk viscosity increases significantly. Thus, there is a clear correlation between transition temperatures in the adsorbed layer and in bulk solution, and we discuss this in relation to a newly proposed model that considers competition between aggregation and adsorption/deposition. A much larger temperature response above the T-2 temperature was found for adsorbed layers of HPMC than for layers of methyl cellulose. Possible reasons for this are discussed.

  • 132. Bohner, B.
    et al.
    Endrodi, Balazs
    Horváth, D.
    Tóth, Á.
    Flow-driven pattern formation in the calcium-oxalate system2016In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 144Article in journal (Refereed)
    Abstract [en]

    The precipitation reaction of calcium oxalate is studied experimentally in the presence of spatial gradients by controlled flow of calcium into oxalate solution. The density difference between the reactants leads to strong convection in the form of a gravity current that drives the spatiotemporal pattern formation. The phase diagram of the system is constructed, the evolving precipitate patterns are analyzed and quantitatively characterized by their diameters and the average height of the gravity flow. The compact structures of calcium oxalate monohydrate produced at low flow rates are replaced by the thermodynamically unstable calcium oxalate dihydrate favored in the presence of a strong gravity current.

  • 133. Brandner, Birgit D.
    et al.
    Hansson, Petra M.
    Swerin, Agne
    Claesson, Per Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Wahlander, Martin
    Schoelkopf, Joachim
    Gane, Patrick A. C.
    Solvent segregation and capillary evaporation at a superhydrophobic surface investigated by confocal Raman microscopy and force measurements2011In: SOFT MATTER, ISSN 1744-683X, Vol. 7, no 3, p. 1045-1052Article in journal (Refereed)
    Abstract [en]

    Wetting of water, a 1 : 1 water/ethanol mixture and an aqueous dodecylbenzene sulfonic acid surfactant solution on hydrophobic and superhydrophobic surfaces were studied using confocal Raman microscopy. The superhydrophobic surfaces were prepared by immersion of a glass substrate in a silica particle/fluoropolymer formulation followed by silanization. Preparation of hydrophobic surfaces was done in the same way with the exception that the silica particles were excluded from the formulation. The hydrophobic and superhydrophobic surfaces were characterized with respect to surface roughness using AFM, and by contact angle measurements using different liquids. Confocal Raman microscopy measurements in a 1 : 1 water/ethanol mixture showed an enrichment of ethanol close to the superhydrophobic surface, which could not be observed for the hydrophobic surface. Unexpectedly, the Raman spectrum of a pure water film in close proximity to the superhydrophobic surface displayed some differences compared to that of bulk water and indicated a stronger hydrogen-bonding close to the superhydrophobic surface. Evidence for capillary evaporation next to the superhydrophobic surface was also found, and this results in very long-range capillary attraction between one superhydrophobic surface and a hydrophobic colloidal probe as shown by AFM colloidal probe force measurements. Addition of a surfactant or ethanol suppresses capillary evaporation.

  • 134.
    Brett, Calvin
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Neutron and X-ray Surface Scattering Reveals the Morphology of Soft Matter Thin Films2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The last decades have been overshadowed by reports about the seemingly endless increase use of fossil-based resources. With the development of new products, our mindset is changing so that we more and more need to consider sustainability in our daily lives. Furthermore, smarter devices are indispensable in our world and daily life, and these are expected to be smaller and smaller in size.

    To support the transition from fossil-based to sustainable materials, we need to develop knowledge of new materials. Within this thesis project, the aim has been to understand the thin-film properties of sustainable materials and to develop methodologies to measure these. As sustainable template material wood-based nanocellulose was chosen as a bio-degradable representative with favourable favourable physical properties, such as lightweight, transparency, and flexibility. These properties make nanocellulose a perfect candidate for future advanced applications in thin-film organic solar cells, supercapacitors, or sensors. Nanocellulose comprises only a part of such a device, and hence the relevant functional materials and their combinations have to be studied to reveal the interaction between multiple material components on the final device performance. As the nanoscale, or even Ångstrom scale, governs the macroscopic physical properties, it is crucial to understand the materials in detail. Ergo, neutron and X-ray surface-sensitive scattering methods were applied to study nanoparticle deposition layering kinetics and the effects of environmental changes, which revealed the morphology of the resulting nanoporous nanocellulose thin films. The knowledge was used to infiltrate water-soluble intrinsic conductive polymers into these nanopores, which serves as a model for transparent but conductive templates for organic electronics. By changing the environment of the films through humidity cycling, the impact of the environment during a real-life application could be illustrated. Neutron scattering experiments also showed that the cellulose-conductive polymer composite (or hybridmaterial) changes irreversibly during humidity cycling while the pure nanocellulose films show fully reversible properties.

    Furthermore, the thermal decomposition of silver nitrate deposited on nanocellulose was studied to understand the nanofibrils' impact on the synthesis of nanoparticles. The transparency allowed in situ studies of the synthesis process, the spectroscopic properties as well as the plasmonic effect, which demonstrated routes for minimal material usage concepts for surface synthesis processes. It was also discovered that the process allows for band-gap tuning, which can be directly be applied in organic solar cells to tailor the band-gap to be adapted and hence increasing the efficiency.The morphological properties, as studied using X-rays and neutrons, were correlated to macroscopic properties by measuring wettability, surface topography, spectroscopy, or conductivity to examine the full materials application possibilities. Neutron and X-ray scattering methods are complementary and wisely combined, thus allowed pioneering studies of bio-based sustainable nanocomposites leading to advanced functional material concepts that support the development of devices using less fossil-based materials.

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  • 135.
    Brett, Calvin
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Forslund, Ola Kenji
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Nocerino, Elisabetta
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Kreuzer, Lucas
    Wiedmann, Tobias
    Porcar, Lionel
    Yamada, Norifumi
    Matsubara, Nami
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Månsson, Martin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Müller-Buschbaum, Peter
    Söderberg, Daniel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fiberprocesser.
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Humidity-induced Nanoscale Restructuring in PEDOT:PSS and Cellulose reinforced Bio-based Organic ElectronicsManuscript (preprint) (Other academic)
  • 136.
    Brett, Calvin
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Ohm, Wiebke
    Fricke, Björn
    Laarmann, Tim
    Körstgens, Volker
    Müller-Buschbaum, Peter
    Söderberg, Daniel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fiberprocesser.
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Nanocellulose-Assisted Thermally-Induced Growth of Silver Nanoparticles for Optical ApplicationsManuscript (preprint) (Other academic)
  • 137. Briggner, Lars-Erik
    et al.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Rosdahl, Jan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Svensson, Per H.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    In Silico Solid State Perturbation for Solubility Improvement2014In: ChemMedChem, ISSN 1860-7179, E-ISSN 1860-7187, Vol. 9, no 4, p. 724-726Article in journal (Refereed)
    Abstract [en]

    Solubility is a frequently recurring issue within pharmaceutical industry, and new methods to proactively resolve this are of fundamental importance. Here, a novel methodology is reported for intrinsic solubility improvement, using insilico prediction of crystal structures, by perturbing key interactions in the crystalline solid state. The methodology was evaluated with a set of benzodiazepine molecules, using the two-dimensional molecular structure as the only a priori input. The overall trend in intrinsic solubility was correctly predicted for the entire set of benzodiazepines molecules. The results also indicate that, in drug compound series where the melting point is relatively high (i.e., brick dust compounds), the reported methodology should be very suitable for identifying strategically important molecular substitutions to improve solubility. As such, this approach could be a useful predictive tool for rational compound design in the early stages of drug development.

  • 138.
    Brinck, Tore
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Green Energetic Materials2014Collection (editor) (Other academic)
    Abstract [en]

    Since the end of the 20th century it has been increasingly realised that the use, or production, of many energetic materials leads to the release of substances which are harmful to both humans and the environment. To address this, the principles of green chemistry can be applied to the design of new products and their manufacturing processes, to create green energetic materials that are virtually free of environmental hazards and toxicity issues during manufacturing, storage, use and disposal. Active research is underway to develop new ingredients and formulations, green synthetic methods and non-polluting manufacturing processes. Green Energetic Materials provides a detailed account of the most recent research and developments in the field, including green pyrotechnics, explosives and propellants. From theoretical modelling and design of new materials, to the development of sustainable manufacturing processes, this book addresses materials already on the production line, as well as considering future developments in this evolving field. Topics covered include: • Theoretical design of green energetic materials • Development of green pyrotechnics • Green primary and secondary explosives • Oxidisers and binder materials for green propellants • Environmentally sustainable manufacturing technologies for energetic materials • Electrochemical methods for synthesis of energetic materials and waste remediation Green Energetic Materials is a valuable resource for academic, industrial and governmental researchers working on the development of energetic materials, for both military and civilian applications.

  • 139.
    Brinck, Tore
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Preface2014In: Green Energetic Materials, Wiley-Blackwell, 2014, p. xi-xiiChapter in book (Refereed)
  • 140.
    Brinck, Tore
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Borrfors, Andre Nyberg
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    The Importance of Electrostatics and Polarization for Noncovalent Interactions: Ionic Hydrogen Bonds vs Ionic Halogen Bonds2022In: Journal of Molecular Modeling, ISSN 1610-2940, E-ISSN 0948-5023, Vol. 28, no 9, article id 275Article in journal (Refereed)
    Abstract [en]

    A series of 26 hydrogen-bonded complexes between Br- and halogen, oxygen and sulfur hydrogen-bond (HB) donors is investigated at the M06-2X/6-311 +G(2df,2p) level of theory. Analysis using a model in which Br- is replaced by a point charge shows that the interaction energy (Delta E-Int) of the complexes is accurately reproduced by the scaled interaction energy with the point charge (Delta E-Int(PC)). This is demonstrated by Delta E-Int = 0.86 Delta E-Int(PC) with a correlation coefficient, R-2=0.999. The only outlier is (Br-H-Br)(-), which generally is classified as a strong charge-transfer complex with covalent character rather than a HB complex. Delta E-Int(PC) can be divided rigorously into an electrostatic contribution (Delta E-ES(PC)) and a polarization contribution (Delta E-pol(PC)).Within the set of HB complexes investigated, the former varies between -7.2 and -32.7 kcal mol(-1), whereas the latter varies between -1.6 and -11.5 kcal mol(-1). Compared to our previous study of halogen-bonded (XB) complexes between Br and C-Br XB donors, the electrostatic contribution is generally stronger and the polarization contribution is generally weaker in the HB complexes. However, for both types of bonding, the variation in interaction strength can be reproduced accurately without invoking a charge-transfer term. For the Br-center dot center dot center dot HF complex, the importance of charge penetration on the variation of the interaction energy with intermolecular distance is investigated. It is shown that the repulsive character of Delta E-Int at short distances in this complex to a large extent can be attributed to charge penetration.

  • 141.
    Brinck, Tore
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Haeberlein, Markus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    A Computational Analysis of Substituent Effects on the O-H Bond Dissociation Energy in Phenols: Polar Versus Radical Effects1997In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 119, no 18, p. 4239-4244Article in journal (Refereed)
  • 142.
    Brinck, Tore
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Lee, Hau-Nan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Quantum Chemical Studies on the Thermochemistry of Alkyl and Peroxyl Radicals.1999In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 103, p. 7094-7104-Article in journal (Refereed)
  • 143.
    Brinck, Tore
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Rahm, M.
    Theoretical Design of Green Energetic Materials: Predicting Stability, Detection, Synthesis and Performance2014In: Green Energetic Materials, Wiley-Blackwell, 2014, p. 15-44Chapter in book (Other academic)
    Abstract [en]

    The objective of this chapter is to illustrate the use of modern quantum chemical methods in the rational design of energetic materials with targeted properties. In the first part we discuss the methods that are used for prediction of thermochemical data, and for analysis of decomposition pathways and kinetic stabilities of new compounds. We also describe how quantum chemical methods can be used for predicting spectroscopic data, synthesis pathways, and performance characteristics of energetic materials. In the remaining part of the chapter we provide examples of the theoretical characterization of a number of compounds with promising properties for use in green propellants. Two of these, 1-nitro-2-oxo-3-amino-triazene and tetraazatetrahedrane, combine high kinetic stabilities with excellent propulsion performance.

  • 144.
    Brinck, Tore
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Sahoo, Suman Kalyan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Anomalous π-backbonding in complexes between B(SiR3)3 and N2: catalytic activation and breaking of scaling relations2023In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 25, no 31, p. 21006-21019Article in journal (Refereed)
    Abstract [en]

    Chemical transformations of molecular nitrogen (N2), including the nitrogen reduction reaction (NRR), are difficult to catalyze because of the weak Lewis basicity of N2. In this study, it is shown that Lewis acids of the types B(SiR3)3 and B(GeR3)3 bind N2 and CO with anomalously short and strong B-N or B-C bonds. B(SiH3)3·N2 has a B-N bond length of 1.48 Å and a complexation enthalpy of −15.9 kcal mol−1 at the M06-2X/jun-cc-pVTZ level. The selective binding enhancement of N2 and CO is due to π-backbonding from Lewis acid to Lewis base, as demonstrated by orbital analysis and density difference plots. The π-backbonding is found to be a consequence of constructive orbital interactions between the diffuse and highly polarizable B-Si and B-Ge bond regions and the π and π* orbitals of N2. This interaction is strengthened by electron donating substituents on Si or Ge. The π-backbonding interaction is predicted to activate N2 for chemical transformation and reduction, as it decreases the electron density and increases the length of the N-N bond. The binding of N2 and CO by the B(SiR3)3 and B(GeR3)3 types of Lewis acids also has a strong σ-bonding contribution. The relatively high σ-bond strength is connected to the highly positive surface electrostatic potential [VS(r)] above the B atom in the tetragonal binding conformation, but the σ-bonding also has a significant coordinate covalent (dative) contribution. Electron withdrawing substituents increase the potential and the σ-bond strength, but favor the binding of regular Lewis acids, such as NH3 and F−, more strongly than binding of N2 and CO. Molecules of the types B(SiR3)3 and B(GeR3)3 are chemically labile and difficult to synthesize. Heterogenous catalysts with the wanted B(Si-)3 or B(Ge-)3 bonding motif may be prepared by boron doping of nanostructured silicon or germanium compounds. B-doped and hydrogenated silicene is found to have promising properties as catalyst for the electrochemical NRR.

  • 145.
    Bruhn, Benjamin
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Qejvanaj, Fatjon
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Sychugov, Ilya
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Linnros, Jan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Blinking Statistics and Excitation-Dependent Luminescence Yield in Si and CdSe Nanocrystals2014In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 118, no 4, p. 2202-2208Article in journal (Refereed)
    Abstract [en]

    ON-OFF intermittency or blinking is a phenomenon observed in single quantum emitters, which reduces their overall light emission. Even though it seems to be a fundamental property of quantum dots (QDs), substantial differences can be found in the blinking statistics of different nanocrystals. This work compares the blinking of numerous single, oxide-capped Si nanocrystals with that of CdSe/ZnS core-shell nanocrystals, measured under the same conditions in the same experimental system and over a broad range of excitation power densities. We find that ON- and OFF-times can be described by exponential statistics in Si QDs, as opposed to power-law statistics for the CdSe nanocrystals. The type of blinking (power-law or monoexponential) does not depend on excitation but seems to be an intrinsic property of the material system. Upon increasing excitation power, the duty cycle of Si quantum dots remains constant, whereas it decreases for CdSe nanocrystals, which is readily explained by blinking statistics. Both ON-OFF and OFF-ON transitions can be regarded as light-induced in Si/SiO2 QDs, while the OFF-ON transition in CdSe/ZnS nanocrystals is not stimulated by photons. The differences in blinking behavior in these systems will be discussed.

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  • 146.
    Bryngelsson, Erik
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Manufacturing optimization and film stability analysis of PbS quantum dot solar cells2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Semiconductor colloidal quantum dots have an interesting potential to increase solar cell efficiency, with strong absorption in the infrared region and a tunable band gap. In this work an attempt was made to adopt a manufacturing process for PbS quantum dot solar cells, proven successful at Uppsala University. Two optimizations were investigated and the stability of the quantum dot films was analyzed with regards to three storage conditions, varying oxygen accessibility and light exposure, and measured with UV-Vis spectroscopy and X-ray photoelectron spectroscopy. Functioning solar cells were obtained but with lower performance than the results from Uppsala. Optimizations were partly successful with regards to improved spreading of the EDT solution on the PbS quantum dot film using ethanol and methanol as solvents. No improved cell performance was observed by applying both QD films inside argon atmosphere, as opposed to only the first one. Clear differences in oxidization of the films and loss of iodine ligand could be identified for the different storage conditions, with best stability exhibited by films stored under argon atmosphere.

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  • 147.
    Budnyak, Tetyana
    et al.
    KTH. Natl Acad Sci Ukraine, Chuiko Inst Surface Chem, 17 Gen Naumov St, UA-03164 Kiev, Ukraine..
    Gladysz-Plaska, Agnieszka
    Marie Curie Sklodowska Univ, 2 Marie Curie Sklodowska Sq, PL-20031 Lublin, Poland..
    Strizhak, Alexander V.
    Taras Shevchenko Natl Univ Kyiv, 64-13 Volodymyrska St, UA-01601 Kiev, Ukraine..
    Sternik, Dariusz
    Marie Curie Sklodowska Univ, 2 Marie Curie Sklodowska Sq, PL-20031 Lublin, Poland..
    Komarov, Igor V.
    Taras Shevchenko Natl Univ Kyiv, 64-13 Volodymyrska St, UA-01601 Kiev, Ukraine..
    Majdan, Marek
    Marie Curie Sklodowska Univ, 2 Marie Curie Sklodowska Sq, PL-20031 Lublin, Poland..
    Tertykh, Valentin A.
    Natl Acad Sci Ukraine, Chuiko Inst Surface Chem, 17 Gen Naumov St, UA-03164 Kiev, Ukraine..
    Imidazole-2yl-Phosphonic Acid Derivative Grafted onto Mesoporous Silica Surface as a Novel Highly Effective Sorbent for Uranium(VI) Ion Extraction2018In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 7, p. 6681-6693Article in journal (Refereed)
    Abstract [en]

    A new imidazol-2yl-phosphonic acid/mesoporous silica sorbent (ImP(O)(OH)(2)/SiO2) was developed and applied for uranium(VI) ion removal from aqueous solutions. The synthesized material was characterized by fast kinetics and an extra-high adsorption capacity with respect to uranium. The highest adsorption efficiency of U(VI) ions was obtained for the reaction system at pH 4 and exceeded 618 mg/g. The uranium(VI) sorption proceeds quickly in the first step within 60 min of the adsorbent sites and ion interactions. Moreover, the equilibrium time was determined to be 120 min. The equilibrium and kinetic characteristics of the uranium(VI) ions uptake by synthesized sorbent was found to follow the Langmuir-Freundlich isotherm model and pseudo-second-order kinetics rather than the Langmuir, Dubinin-Radushkevich, and Temkin models and pseudo-first-order or intraparticle diffusion sorption kinetics. The adsorption mechanism for uranium on the sorbent was clarified basing on the X-ray photoelectron spectroscopy (XPS) analysis. The model of UO22+ binding to surface of the sorbent was proposed according to the results of XPS, i.e., a 1:1 U-to-P ratio in the sorbed complex was established. The regeneration study confirms the ImP(O)(OH)(2)/SiO2 sorbent can be reused. A total of 45% of uranium ions was determined as originating from the sorbent leaching in the acidic solutions, whereas when the basic solutions were used, the removal efficiency was 12%.

  • 148.
    Budnyak, Tetyana M.
    et al.
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden..
    Modersitzki, Sina
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden..
    Pylypchuk, Ievgen
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Wood Chemistry and Pulp Technology.
    Piatek, Jedrzej
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden..
    Jaworski, Aleksander
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden..
    Sevastyanova, Olena
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Lindström, Mikael
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Slabon, Adam
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden..
    Tailored Hydrophobic/Hydrophilic Lignin Coatings on Mesoporous Silica for Sustainable Cobalt(II) Recycling2020In: ACS Sustainable Chemistry and Engineering, E-ISSN 2168-0485, Vol. 8, no 43, p. 16262-16273Article in journal (Refereed)
    Abstract [en]

    Lignin is a renewable biopolymer, and its chemical functionalization renders it a prospective material for a plethora of applications. Within this respect, we present a method for lignin immobilization on the surface of mesoporous silica. Two types of lignins were used to prove the feasibility of the fabrication of either hydrophilic or hydrophobic biocoatings on silica. The procedure permits to immobilize 17 mg of lignosulfonate (LS) or 37 mg of kraft lignin (KL) per gram of silica. The bioinorganic composites display a synergistic effect in the adsorption of cobalt(II) ions from aqueous solutions because the adsorption efficiency outperforms the individual constituents. These results demonstrate that thin lignin overlayers, exhibiting polymer concentrations of 0.07 mg.m(-2) for LS-SiO2, and 0.14 mg.m(-2) for KL-SiO2, provide new functionality in comparison to bulk lignin and metal oxides. According to the Langmuir isotherm model, the adsorption capacity toward aqua complexes of Co(II) was found to be 75 and 59 mg.g(-1) for the LS- or KL-coated silica, respectively. The kinetic study revealed that lignin-SiO2 composites gained the features of inorganic sorbents because 1-1.5 h was sufficient for effective cobalt extraction. The adsorption on the bioinorganic composites proceeds with the pseudo-second-order kinetics model. The adsorption of Co(II) ions was confirmed by means of solid-state H-1 magic-angle spinning (MAS) NMR spectroscopy. The simplicity of the synthesis, low-cost and abundancy of substrates, high capacity, and fast kinetics make such lignin-coated silica a promising material for cobalt recovery.

  • 149.
    Burger, Friedrich Anton
    et al.
    Albert Ludwigs Univ Freiburg, Phys Inst, D-79104 Freiburg, Germany..
    Corkery, Robert
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. KTH Royal Inst Technol, Appl Phys Chem, SE-10044 Stockholm, Sweden.;Australian Natl Univ, Res Sch Phys, Dept Appl Math, Canberra, ACT 2601, Australia..
    Buhmann, Stefan Yoshi
    Albert Ludwigs Univ Freiburg, Phys Inst, D-79104 Freiburg, Germany..
    Fiedler, Johannes
    Albert Ludwigs Univ Freiburg, Phys Inst, D-79104 Freiburg, Germany.;Univ Oslo, Ctr Mat Sci & Nanotechnol, Dept Phys, NO-0316 Oslo, Norway..
    Comparison of Theory and Experiments on van der Waals Forces in Media-A Survey2020In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 124, no 44, p. 24179-24186Article in journal (Refereed)
    Abstract [en]

    We present a critical overview comparing theoretical predictions and measurements of van der Waals dispersion forces in media on the basis of the respective Hamaker constants. To quantify the agreement, we complement the reported experimental errors with those for the theoretical predictions, which are because of the uncertainties in the underlying spectroscopic data. Our main finding is that the theoretical errors are often larger than their experimental counterparts. Within these uncertainties, the comparison confirms the standard Lifshitz theory based on the Abraham electromagnetic stress tensor against the recently suggested alternative account on the basis of the Maxwell stress tensor.

  • 150. Bydén, M.
    et al.
    Edlund, H.
    Berglund, P.
    Mid Sweden university.
    Lindström, B.
    Phase equilibria in two aqueous chiral surfactant systems1997In: Progress in Colloid and Polymer Science, ISSN 0340-255X, E-ISSN 1437-8027, Vol. 105, p. 360-364Article in journal (Refereed)
    Abstract [en]

    In this study, we present the binary phase diagrams of the pure (R)- and the racemic aqueous sodium-2-methyldecanoate surfactant systems. The latter is a 1:1 mixture of the pure (S)- and pure (R)-form. The systems were investigated using crossed polaroids, polarizing optical microscope and 2HNMR splittings. Both systems form a micellar phase, followed by a hexagonal, some intermediate phase and a large cubic phase. At even higher concentrations, the 2HNMR studies showed larger quadrupolar splittings up to 1200 Hz, due to a lamellar phase. The intermediate phase was in both cases very narrow, and extended up to > 23°C in the racemic system and up to 30°C in the pure (R)-system. The similarity between these two binary phase diagrams indicates that the change in molecular packing is so small that it does not drastically affect the phase behavior. The Krafft temperature in the micellar phase in both systems is 1°C, which is very low compared to that of unsubstituted alkanoates with the same chain length.

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