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  • 901.
    Yoshioka, Takanori
    et al.
    KTH.
    Shimamura, Yuta
    Karasev, Andrey
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Ohba, Yasuhide
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Mechanism of a CaS Formation in an Al-Killed High-S Containing Steel during a Secondary Refining Process without a Ca-Treatment2017In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 88, no 10, article id UNSP 1700147Article in journal (Refereed)
  • 902. Yu, Shujun
    et al.
    Wang, Xiangxue
    Yao, Wen
    Wang, Jian
    Ji, Yongfei
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Ai, Yuejie
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Alsaedi, Ahmed
    Hayat, Tasawar
    Wang, Xiangke
    Macroscopic, Spectroscopic, and Theoretical Investigation for the Interaction of Phenol and Naphthol on Reduced Graphene Oxide2017In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, no 6, p. 3278-3286Article in journal (Refereed)
    Abstract [en]

    Interaction of phenol and naphthol with reduced graphene oxide (rGO), and their competitive behavior on rGO were examined by batch experiments, spectroscopic analysis and theoretical calculations. The batch sorption showed that the removal percentage of phenol or naphthol on rGO in bisolute systems was significantly lower than those of phenol or naphthol in single-solute systems. However, the overall sorption capacity of rGO in bisolute system was higher than single-solute system, indicating that the rGO was a very suitable material for the simultaneous elimination of organic pollutants from aqueous solutions. The interaction mechanism was mainly pi-pi interactions and hydrogen bonds, which was evidenced by FTIR, Raman and theoretical calculation. FTIR and Raman showed that a blue shift of C=C and -OH stretching modes and the enhanced intensity ratios of I-D/I-G after phenols sorption. The theoretical calculation indicated that the total hydrogen bond numbers, diffusion constant and solvent accessible surface area of naphthol were higher than those of phenol, indicating higher sorption affinity of rGO for naphthol as compared to phenol. These findings were valuable for elucidating the interaction mechanisms between phenols and graphene-based materials, and provided an essential start in simultaneous removal of organics from wastewater.

  • 903.
    Yu, Shun
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Ahmadi, Sareh
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Sun, Chenghua
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Palmgren, Pal
    Hennies, Franz
    Zuleta, Marcelo
    Göthelid, Mats
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    4-tert-Butyl Pyridine Bond Site and Band Bending on TiO2(110)2010In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 114, no 5, p. 2315-2320Article in journal (Refereed)
    Abstract [en]

    In the present work, we study the bonding of 4-tert-butyl pyridine (4TBP) to the TiO2(110) surface using photoelectron spectroscopy (PES) and density functional theory (DFT) calculations. The results show that at low coverage, 4TBP adsorbs preferentially on oxygen vacancies. The calculated adsorption energy at the vacancies is 120 kJ/mol larger than that oil the five-fold-coordinated Ti4+ sites located in the rows on the TiO2 surface. The vacancy is "healed" by 4TBP, and the related gap state is strongly reduced through charge transfer into empty pi* orbitals on the pyridine ring. This leads to a change in surface band bending by 0.2 eV toward lower binding energies. The band bending does not change with further 4TBP deposition when saturating the surface to monolayer coverage, where the TiO2 surface is effectively protected against further adsorption by the dense 4TBP layer.

  • 904. Yu, Xinhai
    et al.
    Li, Hongliang
    Tu, Shan-Tung
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Wang, Zhengdong
    Pt-Co catalyst-coated channel plate reactor for preferential CO oxidation2011In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 36, no 5, p. 3778-3788Article in journal (Refereed)
    Abstract [en]

    To achieve preferential CO oxidation, a Pt-Co catalyst-coated channel plate reactor (CCPR) was produced via conventional mechanical milling and catalyst coating. The proposed reactor performed well under a wide range of operating temperatures and provided satisfactory results at low temperatures (CO concentrations of 1-10 ppm at 413-443 K and 1-50 ppm at 413-453 K). In the proposed CCPR, significant deactivation was not observed during continuous operation for 100 h. In addition, the reactor exhibited excellent tolerance to undesirable conditions, including reaction temperature runaway and feeding stream failure. Characterisation results indicated that the catalytic activity of the proposed CCPR was high due to the formation of Pt3Co intermetallic compounds and nanoscale metal particles. The capacity per channel of the proposed CCPR was approximately 50-100 times greater than those of conventional microchannel reactors; thus, problems associated with excessive reactors were significantly reduced. In general, the results indicated that CCPR has great potential in the small-scale production of hydrogen for fuel cells.

  • 905.
    Yu, Ze
    et al.
    State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis, DUT-KTH Joint Education and Research Center on Molecular Devices, Dalian University of Technology (DUT), Dalian, 116024, China.
    Sun, Licheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry. State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis, DUT-KTH Joint Education and Research Center on Molecular Devices, Dalian University of Technology (DUT), Dalian, 116024, China.
    Inorganic Hole-Transporting Materials for Perovskite Solar Cells2018In: Small Methods, ISSN 2366-9608, Vol. 2, no 2, article id 1700280Article in journal (Refereed)
    Abstract [en]

    In the last few years, inorganic–organic metal halide perovskite solar cells (PSCs) have attracted a great deal of attention as a promising next-generation solar-cell technology because of their high efficiencies and low production cost. Hole-transporting materials (HTMs) play an essential role in effective charge extraction and thus in achieving high overall efficiency. Therefore, searching for an efficient, stable, and low-cost HTM in PSCs has been one of the hottest research topics in this field. Inorganic p-type semiconductors that possess several appealing characteristics, such as suitable energy levels, high hole mobility, and high chemical stability, as well as low production cost, etc., are promising HTM candidate materials in PSCs. Here, specific attention is paid to the recent progress in inorganic HTMs being explored for PSCs. A variety of methods developed for the fabrication of these inorganic HTMs are summarized in detail, together with their corresponding performance in PSCs. Finally, an outlook on further enhancements of highly efficient PSCs based on inorganic HTMs is presented.

  • 906.
    Yushmanov, Pavel
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Industrial NMR Centre.
    Furó, István
    KTH, School of Chemical Science and Engineering (CHE), Centres, Industrial NMR Centre.
    Iliopoulos, Ilias
    Kinetics of demixing and remixing transitions in aqueous solutions of poly(N-isopropylacrylamide):  A temperature-jump H-1 NMR study2006In: Macromolecular Chemistry and Physics, ISSN 1022-1352, E-ISSN 1521-3935, Vol. 207, no 21, p. 1972-1979Article in journal (Refereed)
    Abstract [en]

    The time course of the coil-to-globule collapse and intermolecular aggregation of poly(N-isopropylacrylamide) in aqueous solution upon exceeding the lower critical solution temperature (LCST) are investigated by temperature-jump 1H NMR spectroscopy. After the temperature jump, we record the time dependences of (i) the mobile fraction of the polymer chain as revealed by the intensity of the liquid-like NMR signal, (ii) the local mobility of those chains as revealed by the transverse relaxation time T2, and (iii) their self-diffusion coefficient D. The same data are also reported at their temperature-dependent long-time limits. The results suggest a sudden, faster than one second, collapse and intermolecular aggregation into globules and a slower reorganization/redistribution of the individual chains among and within the globular and mobile states. We found that all molecular changes are reversible if the temperature remains less than ca. 6-8 K above the LCST for less than a few minutes; under those conditions, experiments upon sudden temperature quench below the LCST show that the aggregates disintegrate and swell into coils in less than a few seconds.

  • 907.
    Yushmanov, Pavel V.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    NMR Studies of Colloidal Systems in and out of Equilibrium2006Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The Thesis describes (i) the development of add-on instrumentation extending the capabilities of conventional NMR spectrometers and (ii) the application of the designed equipments and techniques for investigating various colloidal systems. The new equipments are:

    Novel designs of stopped-flow and temperature–jump inserts intended for conventional Bruker wide-bore superconductive magnets. Both inserts are loaded directly from above into the probe space and can be used together with any 10 mm NMR probe with no need for any auxiliary instruments.

    A set of 5 mm and 10 mm 1H – 19F – 2H NMR probes designed for heteronuclear 1H – 19F cross-relaxation experiments in Bruker DMX 200, AMX 300 and DMX 500 spectrometers, respectively.

    A two–stage low-pass filter intended for suppressing RF noise in electrophoretic NMR experiments.

    The kinetics of micellar dissolution and transformation in aqueous solutions of sodium perfluorooctanoate (NaPFO) is investigated using the stopped-flow NMR instrument. The sensitivity of NMR as detection tool for kinetic processes in micellar solutions is clarified and possible artefacts are analysed. In the NaPFO system, the micellar dissolution is found to proceed faster than 100 ms while surfactant precipitation occurs on the time scale of seconds-to-minutes. The kinetics of the coil-to–globule transition and intermolecular aggregation in a poly (Nisopropylacrylamide) solution are investigated by the temperature-jump NMR instrument. As revealed by the time evolution of the 1H spectrum, the T2 relaxation time and the self-diffusion coefficient D, large (>10 nm) and compact aggregates form in less than 1 second upon fast temperature increase and dissolve in less than 3 seconds upon fast temperature decrease.

    The intermolecular 1H – 19F dipole-dipole cross-relaxation between the solvent and solute molecules, whose fast rotational diffusion is in the extreme narrowing limit, is investigated. The solutes are perfluorooctanoate ions either in monomeric or in micellar form and trifluoroacetic acid and the solvent is water. The obtained cross-relaxation rates are frequency-dependent which clearly proves that there is no extreme narrowing regime for intermolecular dipole-dipole relaxation. The data provide strong constraints for the dynamic retardation of solvent by the solute.

  • 908.
    Yushmanov, Pavel V.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Furó, Istvan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Stilbs, Peter
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Stopped-flow F-19 NMR studies of surfactant precipitation2006In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, E-ISSN 1873-4359, Vol. 291, no 1-3, p. 59-62Article in journal (Refereed)
    Abstract [en]

    The kinetics of the phase change in surfactant solutions is studied by F-19 stopped-flow NMR. In the aqueous solution of sodium perfluooctanoate, we observe precipitation and crystal growth induced by the addition of NaCl solution to the system. The time dependences of the NMR signal intensity and chemical shift, evaluated in the framework of a single model, narrow the range of possible scenarios, the most plausible of which is monomer incorporation into the growing crystals. In accordance to existing models of crystallization, both the nucleation rates and the crystal growth rates are strongly dependent on the magnitude of supersaturation.

  • 909. Zambrano, Noelia
    et al.
    Tyrode, Eric
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Mira, Isabel
    Marquez, Laura
    Rodriguez, Maria-Patricia
    Salager, Jean-Louis
    Emulsion Catastrophic Inversion from Abnormal to Normal Morphology. 1. Effect of the Water-to-Oil Ratio Rate of Change on the Dynamic Inversion Frontier2003In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 42, no 1, p. 50-56Article in journal (Refereed)
    Abstract [en]

    The rate of addn. of the internal phase affects the catastrophic inversion of emulsions in the direction of change from abnormal to normal morphol. At a low addn. rate, the inversion takes place after a small amt. of the internal phase is added, and it happens through the occurrence of multiple emulsion morphol. At a high addn. rate, the inversion appears to be delayed, and it takes place without the occurrence of a multiple emulsion. [on SciFinder (R)]

  • 910.
    Zander, Thomas
    et al.
    Helmholtz Zentrum Geesthacht, Ctr Mat & Costal Res, Inst Mat Res, Max Planck Str 1, D-21502 Geesthacht, Germany..
    Wieland, D. C. Florian
    Helmholtz Zentrum Geesthacht, Ctr Mat & Costal Res, Inst Mat Res, Max Planck Str 1, D-21502 Geesthacht, Germany..
    Raj, Akanksha
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Salmen, Paul
    TU Dortmund, DELTA, Fak Phys, D-44221 Dortmund, Germany..
    Dogan, Susanne
    TU Dortmund, DELTA, Fak Phys, D-44221 Dortmund, Germany..
    Dédinaité, Andra
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. RISE Res Inst Sweden, Div Biosci & Mat, SE-11486 Stockholm, Sweden..
    Garamus, Vasil M.
    Helmholtz Zentrum Geesthacht, Ctr Mat & Costal Res, Inst Mat Res, Max Planck Str 1, D-21502 Geesthacht, Germany..
    Schreyer, Andreas
    Helmholtz Zentrum Geesthacht, Ctr Mat & Costal Res, Inst Mat Res, Max Planck Str 1, D-21502 Geesthacht, Germany..
    Claesson, Per M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. RISE Res Inst Sweden, Div Biosci & Mat, SE-11486 Stockholm, Sweden..
    Willumeit-Roemer, Regine
    Helmholtz Zentrum Geesthacht, Ctr Mat & Costal Res, Inst Mat Res, Max Planck Str 1, D-21502 Geesthacht, Germany..
    Influence of high hydrostatic pressure on solid supported DPPC bilayers with hyaluronan in the presence of Ca2+ ions2019In: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 15, no 36, p. 7295-7304Article in journal (Refereed)
    Abstract [en]

    The molecular mechanisms responsible for outstanding lubrication of natural systems, like articular joints, have been the focus of scientific research for several decades. One essential aspect is the lubrication under pressure, where it is important to understand how the lubricating entities adapt under dynamic working conditions in order to fulfill their function. We made a structural investigation of a model system consisting of two of the molecules present at the cartilage interface, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and hyaluronan, at high hydrostatic pressure. Phospholipid layers are found at the cartilage surfaces and are able to considerably reduce friction. Their behavior under load and varied solution conditions is important as pressures of 180 bar are encountered during daily life activities. We focus on how divalent ions, like Ca2+, affect the interaction between DPPC and hyaluronan, as other investigations have indicated that calcium ions influence their interaction. It could be shown that already low amounts of Ca2+ strongly influence the interaction of hyaluronan with DPPC. Our results suggest that the calcium ions increase the amount of adsorbed hyaluronan indicating an increased electrostatic interaction. Most importantly, we observe a modification of the DPPC phase diagram as hyaluronan absorbs to the bilayer which results in an L-alpha-like structure at low temperatures and a decoupling of the leaflets forming an asymmetric bilayer structure.

  • 911. Zander, Thomas
    et al.
    Wieland, D. C. Florian
    Raj, Akanksha
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Wang, Min
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Nowak, Benedikt
    Krywka, Christina
    Dédinaité, Andra
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. SP Tech Res Inst Sweden.
    Claesson, Per Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. SP Tech Res Inst Sweden.
    Garamus, Vasil M.
    Schreyer, Andreas
    Willumeit-Romer, Regine
    The influence of hyaluronan on the structure of a DPPC-bilayer under high pressures2016In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 142, p. 230-238Article in journal (Refereed)
    Abstract [en]

    The superior lubrication properties of synovial joints have inspired many studies aiming at uncovering the molecular mechanisms which give rise to low friction and wear. However, the mechanisms are not fully understood yet, and, in particular, it has not been elucidated how the biolubricants present at the interface of cartilage respond to high pressures, which arise during high loads of joints. In this study we utilize a simple model system composed of two biomolecules that have been implied as being important for joint lubrication. It consists of a solid supported dipalmitoylphosphatidylcholin (DPPC) bilayer, which was formed via vesicles fusion on a flat Si wafer, and the anionic polysaccharide hyaluronan (HA). We first characterized the structure of the HA layer that adsorbed to the DPPC bilayers at ambient pressure and different temperatures using X-ray reflectivity (XRR) measurements. Next, XRR was utilized to evaluate the response of the system to high hydrostatic pressures, up to 2 kbar (200 MPa), at three different temperatures. By means of fluorescence microscopy images the distribution of DPPC and HA on the surface was visualized. Our data suggest that HA adsorbs to the headgroup region that is oriented towards the water side of the supported bilayer. Phase transitions of the bilayer in response to temperature and pressure changes were also observed in presence and absence of HA. Our results reveal a higher stability against high hydrostatic pressures for DPPC/HA composite layers compared to that of the DPPC bilayer in absence of HA.

  • 912.
    Zelenin, Sergey
    et al.
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    Käller, M.
    Nazarov, A.
    Brismar, H.
    Russom, Aman
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    High density custom microarrays formed by microcompartment amplification on glass surface2014In: 18th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2014, Chemical and Biological Microsystems Society , 2014, p. 1027-1029Conference paper (Refereed)
    Abstract [en]

    Compartmentalization of a single DNA molecule is necessary for digital amplification. In the present study we have developed a microscale isothermal amplification using exponential rolling circle amplification (RCA). RCA was performed in PDMS microcompartments on a microarray glass, with a volume of less than 1 pL. Resulting amplicons were attached to the glass surface and formed a custom array with the density of spots above 2,5 × 105 per cm2. Our technology can be applied for digital amplification of DNA or RNA from a variety of complex biological samples in a microchip format.

  • 913.
    Zhang, Fan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Claesson, Per Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Electrochemical and AFM studies of mussel adhesive protein (Mefp-1) as corrosion inhibitor for carbon steel2011In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 56, no 3, p. 1636-1645Article in journal (Refereed)
    Abstract [en]

    Adsorption of mussel adhesive protein (Mefp-1) derived from the marine mussel Mytilus edulis and its corrosion inhibition for carbon steel were studied by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements in NaCl solutions at 01 4.6. The results indicate that the Mefp-1 confers significant corrosion inhibition of carbon steel, and the chloride concentration of the solution has an influence on the inhibition efficiency. Within a short exposure time, the inhibition efficiency is higher in the solution with a higher chloride concentration, whereas, for longer exposure time, up to one week, higher inhibition efficiency was obtained in the solution with a lower chloride concentration. AFM imaging was used both ex situ and in situ to investigate Mefp-1 adsorption. The in situ AFM measurements enable the protein adsorption on carbon steel to be visualized in real time in the solution. The AFM images illustrate how the Mefp-1 layer is formed on carbon steel. Measurements using bovine serum albumin (BSA) were also performed for comparison. The results showed that BSA also confers significant corrosion inhibition of carbon steel even though the BSA film formation process is slightly different from that of Mefp-1.

  • 914.
    Zhang, Feng
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Ai, Yue-Jie
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Fang, Wei-Hai
    Nonadiabatic histidine dissociation of hexacoordinate heme in neuroglobin protein2010In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215Article in journal (Refereed)
    Abstract [en]

    In the present work, density functional theory and canonical nonadiabatic Monte Carlo transition state theory have been used to investigate histidine dissociation process from the hexacoordinate heme in Ngb protein. The potential energy surfaces (PES) of the lowest singlet, triplet, and quintet states are calculated by stepwise optimization along with the histidine dissociation pathway. Based on the calculated two-dimensional PES, the histidine dissociation rates for the spin-forbidden processes via singlet to triplet and singlet to quintet transitions have been calculated by the nonadiabatic Monte Carlo transition state theory in canonical ensemble. The present study provides a quantitative description on spin-forbidden histidine dissociation processes.

  • 915.
    Zhang, Igor Ying
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Wu, Jianming
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Xu, Xin
    Trends in R-X Bond Dissociation Energies (R-center dot = Me, Et, i-Pr, t-Bu, X-center dot = H, Me, Cl, OH)2010In: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 6, no 5, p. 1462-1469Article in journal (Refereed)
    Abstract [en]

    Trends for R X bond dissociation energies have been examined with density functional methods of B3LYP, BMK, M06-2X, MC3MPW, B2PLYP, MCG3-MPW, and XYG3, as well as 03, MCG3/3, G3X, and 04 theories as functions of alkylation (i.e., IT = Me, Et, i-Pr, (-Bu) and X' substitution (i.e., X' = H, Me, Cl, OH). The results highlight the physical origin of success or failure of each method and demonstrate the good agreement with experimental results for G4, MCG3-MPW, and XYG3. The last holds great promise as a reliable method that is applicable to larger systems.

  • 916.
    Zhang, Qiong
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Tu, Yaoquan
    Tian, He
    Zhao, Yan-Li
    Stoddart, J. Fraser
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Working Mechanism for a Redox Switchable Molecular Machine Based on Cyclodextrin: A Free Energy Profile Approach2010In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 114, no 19, p. 6561-6566Article in journal (Refereed)
    Abstract [en]

    This paper reports the working mechanism for a redox-responsive bistable [2]rotaxane incorporating an alpha-cyclodextrin (alpha-CD) ring (J. Am. Chem. Soc. 2008, 130, 11294-11296), based on free energy profiles obtained from all-atom molecular dynamics simulations. Employing an umbrella sampling technique, the free energy profiles (potential of mean force, PMF) were calculated for the shuttling motion of the alpha-CD ring between a tetrathiafulvalene (TTF) recognition site and a triazole (TZ) unit on the dumbbell of the rotaxane for three oxidation states (0, +1, +2) of the TTF unit. These calculated free energy profiles verified the experimentally observed binding preference for each state. Analysis of the free energy components reveals that, for these alpha-CD-based rotaxanes with charged TTF units, the real driving force for the shuttling in the oxidized states is actually the interactions between water and the rotaxane components, which overwhelms the attractive interactions between the alpha-CD ring and the charged dumbbell. In this work, we put forward a feasible approach to correctly describe the complexation behavior of CD with charged species, that is, free energy profiles obtained from all-atom molecular dynamics simulation.

  • 917.
    Zhang, Wei
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Hua, Yong
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Wang, Linqin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Zhang, Biaobiao
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Li, Yuanyuan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Liu, Peng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Leandri, Valentina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Guo, Yu
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Chen, Hong
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Gardner, James M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Sun, Licheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry. Dalian Univ Technol DUT, DUT KTH Joint Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Kloo, Lars
    The Central Role of Ligand Conjugation for Properties of Coordination Complexes as Hole-Transport Materials in Perovskite Solar Cells2019In: ACS APPLIED ENERGY MATERIALS, ISSN 2574-0962, Vol. 2, no 9, p. 6768-6779Article in journal (Refereed)
    Abstract [en]

    Two zinc-based coordination complexes Y3 and Y4 have been synthesized and characterized, and their performance as hole-transport materials (HTMs) for perovskite solar cells (PSCs) has been investigated. The complex Y3 contains two separate ligands, and the molecular structure can be seen as a disconnected porphyrin ring. On the other hand, Y4 consists of a porphyrin core and therefore is a more extended conjugated system as compared to Y3. The optical and redox properties of the two different molecular complexes are comparable. However, the hole mobility and conductivity of Y4 as macroscopic material are remarkably higher than that of Y3. Furthermore, when employed as hole-transport materials in perovskite solar cells, cells containing Y4 show a power conversion efficiency (PCE) of 16.05%, comparable to the Spiro-OMeTAD-based solar cells with an efficiency around 17.08%. In contrast, solar cells based on Y3 show a negligible efficiency of about 0.01%. The difference in performance of Y3 and Y4 is analyzed and can be attributed to the difference in packing of the nonplanar and planar building blocks in the corresponding materials.

  • 918.
    Zhang, Xiaoliang
    et al.
    Beihang Univ, Sch Mat Sci & Engn, Beijing 100191, Peoples R China..
    Cappel, Ute B.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Jia, Donglin
    Beihang Univ, Sch Mat Sci & Engn, Beijing 100191, Peoples R China..
    Zhou, Qisen
    Beihang Univ, Sch Mat Sci & Engn, Beijing 100191, Peoples R China..
    Du, Juan
    Beihang Univ, Sch Mat Sci & Engn, Beijing 100191, Peoples R China..
    Sloboda, Tamara
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Svanström, Sebastian
    Uppsala Univ, Dept Phys & Astron, Div Mol & Condensed Matter Phys, Box 516, SE-75120 Uppsala, Sweden..
    Johansson, Fredrik O. L.
    Uppsala Univ, Dept Phys & Astron, Div Mol & Condensed Matter Phys, Box 516, SE-75120 Uppsala, Sweden..
    Lindblad, Andreas
    Uppsala Univ, Dept Phys & Astron, Div Mol & Condensed Matter Phys, Box 516, SE-75120 Uppsala, Sweden..
    Giangrisostomi, Erika
    Helmholtz Zentrum Berlin GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Ovsyannikov, Ruslan
    Helmholtz Zentrum Berlin GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Liu, Jianhua
    Beihang Univ, Sch Mat Sci & Engn, Beijing 100191, Peoples R China..
    Rensmo, Håkan
    Uppsala Univ, Dept Phys & Astron, Div Mol & Condensed Matter Phys, Box 516, SE-75120 Uppsala, Sweden..
    Gardner, James M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Johansson, Erik M. J.
    Uppsala Univ, Phys Chem, Dept Chem Angstrom, S-75120 Uppsala, Sweden..
    Probing and Controlling Surface Passivation of PbS Quantum Dot Solid for Improved Performance of Infrared Absorbing Solar Cells2019In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 31, no 11, p. 4081-4091Article in journal (Refereed)
    Abstract [en]

    Surface properties of colloidal quantum dots (CQDs) are critical for the transportation and recombination of the photoinduced charge carrier in CQD solar cells, therefore dominating the photovoltaic performance. Herein, PbS CQD passivated using liquid-state ligand exchange (LSLX) and solid-state ligand exchange (SSLX) strategies are in detail investigated using photoelectron spectroscopy (PES), and solar cell devices are prepared to understand the link between the CQD surface properties and the solar cell function. PES using different energies in the soft and hard Xray regime is applied to study the surface and bulk properties of the CQDs, and the results show more effective surface passivation of the CQDs prepared with the LSLX strategy and less formation of lead-oxide. The CQD solar cells prepared with LSLX strategy show higher performance, and the photoelectric measurements suggest that the recombination of photoinduced charges is reduced for the solar cell prepared with the LSLX approach. Meanwhile, the fabricated solar cells exhibit good stability. This work provides important insights into how to fine-tune the CQD surface properties by improving the CQD passivation, and how this is linked to further improvements of the device photovoltaic performance.

  • 919. Zhang, Zhisen
    et al.
    Shen, Jiawei
    Wang, Hongbo
    Wang, Qi
    Zhang, Junqiao
    Liang, Lijun
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Tu, Yaoquan
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Effects of Graphene Nanopore Geometry on DNA Sequencing2014In: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 5, no 9, p. 1602-1607Article in journal (Refereed)
    Abstract [en]

    In this Letter we assess the effect of graphene nanopore geometries on DNA sequencing by considering DNA fragments including A, T, C, G, and 5-methylcytosine (MC) pulled out of graphene nanopores of different geometries with diameters down to similar to 1 nm. Using steered molecular dynamics simulations it is demonstrated that the bases (A, T, C, G, and MC) can be indentified at single-base resolution through the characteristic peaks on the force profile in a circular graphene nanopore but not in nanopores with other asymmetric geometries. Our study suggests that the graphene nanopore surface should be modified as symmetrically as possible in order to sequence DNA by atomic force microscopy or optical tweezers.

  • 920.
    Zhao, Ke
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Liu, Peng-Wei
    Wang, Chuan-Kui
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Effects of Structural Fluctuations on Two-Photon Absorption Activity of Interacting Dipolar Chromophores2010In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 114, no 33, p. 10814-10820Article in journal (Refereed)
    Abstract [en]

    One- and two-photon absorption properties of organic chromophores consisting of interacting dipolar branches have been studied using density functional response theory in combination with molecular dynamics simulation. Effects of dipole interaction on optical absorptions have been examined. The importance of solvent effects on optical properties of charge-transfer states is explored by means of polarizable continuum model. It is found that for the interacting dipolar molecule with flexible conformations in solutions, the structural fluctuations can result in new spectral features or significant broadening of one-photon absorption spectrum. Our study highlights again the usefulness of the combined quantum chemical and molecular dynamics approach for modeling two-photon absorption materials in solutions.

  • 921. Ziolek, Marcin
    et al.
    Karolczak, Jerzy
    Zalas, Maciej
    Hao, Yan
    Tian, Haining
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Douhal, Abderrazzak
    Aggregation and Electrolyte Composition Effects on the Efficiency of Dye-Sensitized Solar Cells. A Case of a Near-Infrared Absorbing Dye for Tandem Cells2014In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 118, no 1, p. 194-205Article in journal (Refereed)
    Abstract [en]

    Time-resolved laser spectroscopy studies of complete solar cells sensitized with a near-infrared absorbing dye (HY103) and filled with different electrolytes are applied to explain their macroscopic parameters (efficiency and short-circuit current). Particular attention is paid to the effect of coadsorbent, size of cations in electrolyte (lithium vs guanidine ones), and addition of tert-butylpyridine. A complete deactivation scheme in the cell is revealed, and the rates of electron injection and all other processes are explored. For the most efficient electrolyte, the electron injection rate constants are 0.21 ps(-1) from monomers and 0.07 ps(-1) from H-aggregates. Moreover, two important and novel findings are revealed: energy transfer from the excited state of monomers to H-aggregates (with rate constants from 0.04 to 0.25 ps(-1)) and the decrease of internal conversion rate in HY103 attached to the nanoparticles (0.01 ps(-1)) with respect to that of free dye in solution (0.06 ps(-1)). Thus, our study gives more clues to better understand the photobehavior of dye-sensitized solar cells.

  • 922. Ziółek, M.
    et al.
    Martín, C.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Douhal, A.
    Effect of electrolyte composition on electron injection and dye regeneration dynamics in complete organic dye sensitized solar cells probed by time-resolved laser spectroscopy2012In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 116, no 50, p. 26227-26238Article in journal (Refereed)
    Abstract [en]

    Femtosecond time-gated fluorescence and nanosecond flash photolysis studies of seven complete, real titania nanoparticle solar cells sensitized with an efficient organic dye (TH305) were performed in order to investigate the role of the electrolyte composition on the charge transfer dynamics. The electron injection rate constants were found to range from 0.4 to 3.5 ps-1 in iodide-based electrolyte, and they well correlate with the shift of the conduction band edge potential of titania. The lithium cation additives resulted in 2 times faster electron injection rate constant (3.55 ps-1) with respect to that when larger sodium cations were used (1.86 ps-1). However, in the presence of a pyridine derivative component in the electrolyte solution, the electron injection rate constant decreased several times (0.38 ps-1 for Li+ and 0.54 ps-1 for Na+), while the electron injection efficiency was found to be still very high, 96-100%. The dye regeneration by the redox couple under relatively low fluence of excitation beam (0.4 mJ/cm2 giving about 4 electrons per titania nanoparticle) proceeds with an average rate constant of about 40 × 10 3 s-1 and efficiency close to 100%, independent of the electron composition. However, for a larger fluence (2 mJ/cm2) excitation, a titania-dye electron recombination process competes with the dye regeneration and lowers the solar cell efficiency. The effect of self-quenching, high vibrational levels of the dye excited state, and the neat solvent on the electron injection process are also discussed. This study clearly shows that for TH350-based DSSCs the best performance is obtained using Li+ and TBP as additives to the iodide electrolyte, giving the highest open circuit voltage and almost 100% efficiency of electron injection and dye regeneration.

  • 923.
    Öberg, Helena
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Brinck, Tore
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Fragment molecular orbital study of the cAMP-dependent protein kinase catalyzed phosphoryl transfer: a comparison with the differential transition state stabilization method2016In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 18, no 22, p. 15153-15161Article in journal (Refereed)
    Abstract [en]

    The importance of key residues to the activity of the cAMP-dependent protein kinase catalyzed phosphoryl transfer and to the stabilization of the transition state of the reaction has been investigated by means of the fragment molecular orbital (FMO) method. To evaluate the accuracy of the method and its capability of fragmenting covalent bonds, we have compared stabilization energies due to the interactions between individual residues and the reaction center to results obtained with the differential transition state stabilization method (Szarek, et al., J. Phys. Chem. B, 2008, 112, 11819-11826) and observe, despite a size difference in the fragment describing the reaction center, near-quantitative agreement. We have also computed deletion energies to investigate the effect of virtual deletion of key residues on the activation energy. These results are consistent with the stabilization energies and yield additional information as they clearly capture the effect of secondary interactions, i. e. interactions in the second coordination layer of the reaction center. We find that using FMO to calculate deletion energies is a powerful and time efficient approach to analyze the importance of key residues to the activity of an enzyme catalyzed reaction.

  • 924.
    Öhman, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Development of ATR-FTIR Kretschmann Spectroscopy for In situ Studies of Metal / Polymer Interfaces: and its Intergration with EIS for Exposure to Corrosive Conditions2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The environmental stability of a metal / polymer interface is essential for the durability and mechanical stability of constructions in several important areas such as the automotive, offshore, building and aerospace industries. The protective capability of a polymer film is strongly connected to its barrier properties, but the transport of water and corrosive constituents through the polymer and the subsequent processes at the metal surface are complicated to analyse in detail. The surface to be analysed is confined between two media that are impermeable to most probing particles used in conventional analytical techniques. Several methods exist to describe separate parts of the system, but few techniques work atambient pressure and have the capacity to conduct real-time analysis at relevant exposure conditions. In this work, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) in the Kretschmann geometry was successfully employed for systematic studies of metal / polymer interfaces. This technique requires the use of thin metal films deposited on an internal reflection element (IRE). Most studies were performed on aluminium, which is an important structural light-weight material, but also zinc was analysed, being frequently used for corrosion protection of steel. Upon exposure to water and electrolytes, the ATR-FTIR Kretschmann technique was found capable to monitor and to separate early deterioration related processes at the aluminium / polymer interface, including water sorption and transport of ionic species through the polymer film. Other main processes identified were the formation of corrosion products and swelling of the surface-near polymer network. To perform more comprehensive interpretations, a spectro-electrochemical method was further developed for in situ studies of the hidden metal / polymer interfaces. The ATR-FTIR Kretschmann technique was here combined with the complementary acting technique, Electrical Impedance Spectroscopy (EIS). The integrated set-up was able to provide complementary information, with ATR-FTIR Kretschmann being sensitive to the surface-near region and EIS to the whole system. For instance, metal oxidation and delamination processes can be difficult to distinguish by EIS, while on the other hand oxidation and hydration reactions on aluminiumcan be confirmed as IR bands at distinct positions. Delamination and swelling of a polymer both result in negative bands in an IR spectrum, but these processes may be distinguished by EIS as alterations in different frequency regions. While traditional chemical pre-treatments for enhanced hydrolytic stability perform excellent, they are being phased out from industrial applications due to environmental concerns and work health issues. Today there is an intense ongoing research regarding the mechanisms and performance of environmentally friendly pretreatments to develop systems of similar performance, and the analysis of the confined metal / polymer interface is crucial for this development. The capability of the integrated in situ ATR-FTIR Kretschmann and EIS set-up was therefore further applied to systems where a surface pre-treatment had been applied to the metal prior to the organic coating. Studies were first performed on vacuum-evaporated films of zinc treated with a titanium-based conversion coating and further coated with a UV-curing polymer. Alterations of the conversion layer could be detected upon exposure to the electrolyte. Also alkaline-cleaned aluminium coated with an amino-functional silane film and a thermo-curing epoxy top-coat was thoroughlycharacterized by both ATR-FTIR and IRRAS and further investigated upon exposure toelectrolyte and humid air. Changes at the hidden interface were detected upon thermal curingof the epoxy film and during exposure in electrolyte, and the in situ ATR-FTIR Kretschm annanalysis showed a high sensitivity towards alterations in the interfacial region. Complementary studies in the absence of metal could confirm a water uptake within the silane film and water-induced alterations of the siloxane network.

  • 925. Öjekull, J.
    et al.
    Andersson, P. U.
    Någård, M. B.
    Pettersson, J. B. C.
    Neau, A.
    Rosén, S.
    Thomas, R. D.
    Larsson, M.
    Semaniak, J.
    Österdahl, Fabian
    KTH, School of Engineering Sciences (SCI), Physics, Atomic and Molecular Physics.
    Danared, H.
    Källberg, A.
    af Ugglas, M.
    Dissociative recombination of ammonia clusters studied by storage ring experiments2006In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 125, no 19, p. 194306-Article in journal (Refereed)
    Abstract [en]

    Dissociative recombination of ammonia cluster ions with free electrons has been studied at the heavy-ion storage ring CRYRING (Manne Siegbahn Laboratory, Stockholm University). The absolute cross sections for dissociative recombination of H+(NH3)(2), H+(NH3)(3), D+(ND3)(2), and D+(ND3)(3) in the collision energy range of 0.001-27 eV are reported, and thermal rate coefficients for the temperature interval from 10 to 1000 K are calculated from the experimental data and compared with earlier results. The fragmentation patterns for the two ions H+(NH3)(2) and D+(ND3)(2) show no clear isotope effect. Dissociative recombination of X+(NX3)(2) (X=H or D) is dominated by the product channels 2NX(3)+X [0.95 +/- 0.02 for H+(NH3)(2) and 1.00 +/- 0.02 for D+(ND3)(2)]. Dissociative recombination of D+(ND3)(3) is dominated by the channels yielding three N-containing fragments (0.95 +/- 0.05).

  • 926.
    Önsten, Anneli
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Stoltz, Dunja
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Palmgren, Pål
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Yu, Shun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Göthelid, Mats
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Karlsson, Ulf O.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Water Adsorption on ZnO(0001): Transition from Triangular Surface Structures to a Disordered Hydroxyl Terminated phase2010In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 114, no 25, p. 11157-11161Article in journal (Refereed)
    Abstract [en]

    We present room temperature scanning tunneling microscopy and photoemission spectroscopy studies of water adsorption on the Zn-terminated ZnO(0001) surface. Data indicates that the initial adsorption is dissociative leaving hydroxyl groups on the surface. At low water coverage, the adsorption occurs next to the oxygen-terminated step edges, where water is believed to bind to zinc cations leaving off hydrogen atoms to under-coordinated oxygen anions. When increasing the water dose, triangular terraces grow in size and pits diminish until the surface is covered with wide irregular terraces and a large number of small pits. Higher water exposure (20 Langmuir) results in a much more irregular surface. Hydrogen, which is produced in the dissociation reaction is believed to have an important role in the changed surface structure at high exposures. The fact that adsorbed water completely changes the structure of ZnO(0001) is an important finding toward the understanding of this surface at atmospheric conditions.

  • 927.
    Önsten, Anneli
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Weissenrieder, Jonas
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Stoltz, Dunja
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Yu, Shun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Göthelid, Mats
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Karlsson, Ulf O.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Role of defects in surface chemistry on Cu2O(111)2013In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 117, no 38, p. 19357-19364Article in journal (Refereed)
    Abstract [en]

    High-resolution photoemission spectroscopy and scanning tunneling microscopy (STM) have been used to investigate defects on Cu2O(111) and their interaction with water and sulfur dioxide (SO2). Two types of point defects, i.e., oxygen and copper vacancies, are identified. Copper vacancies are believed to be the most important defects in both water and SO2 surface chemistry. Multiply coordinatively unsaturated oxygen anions (OMCUS) such as oxygen anions adjacent to copper vacancies are believed to be adsorption sites for both water and SO2 reaction products. Water adsorption at 150 K results in both molecular and dissociated water. Molecular water leaves the surface at 180 K. At 300 K and even more at 150 K, SO2 interacts with oxygen sites at the surface forming SO 3 species. However, thermal treatment up to 280 K of Cu 2O(111)/SO2 prepared at 150 K renders only SO4 on the surface.

  • 928.
    Österdahl, Kerstin
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Crystallization of iron fluoride trihydrate from mixed acid solutions2005Licentiate thesis, comprehensive summary (Other scientific)
  • 929.
    Östmark, Emma
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Macakova, Lubica
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Auletta, Tommaso
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Malkoch, Michael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Blomberg, Eva
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Dendritic Structures Based on Bis(hydroxymethyl)propionic Acid as Platforms for Surface Reactions2005In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 21, no 10, p. 4512-4519Article in journal (Refereed)
    Abstract [en]

    In this paper we present results related to the self-assembly of different generations of disulfide-cored 2,2-bis(hydroxymethyl)propionic acid-based dendritic structures onto gold surfaces. These molecular architectures, ranging from generation 1 to generation 3, contain removable acetonide protecting groups at their periphery that are accessible for hydrolysis with subsequent formation of OH-terminated surface-attached dendrons. The deprotection has been investigated in detail as a versatile approach to accomplish reactive surface platforms. A special focus has been devoted to the comparison of the properties of the layers formed by hydrolysis of the acetonide moieties directly on the surface and in solution, prior to the layer formation.

16171819 901 - 929 of 929
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