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  • 1. Armstronga, D. A.
    et al.
    Huie, R. E.
    Lymar, S.
    Koppenol, W. H.
    Merényi, Gabor
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Neta, P.
    Stanbury, D. M.
    Steenken, S.
    Wardman, P.
    Standard electrode potentials involving radicals in aqueous solution: Inorganic radicals2013In: BioInorganic Reaction Mechanisms, ISSN 2191-2491, Vol. 9, no 1-4, p. 59-61Article in journal (Refereed)
    Abstract [en]

    Inorganic radicals, such as superoxide and hydroxyl, play an important role in biology. Their tendency to oxidize or to reduce other compounds has been studied by pulse radiolysis; electrode potentials can be derived when equilibrium is established with a well-known reference compound. An IUPAC Task Group has evaluated the literature and produced the recommended standard electrode potentials for such couples as (O2/O2 ·-), (HO·, H+/H2O), (O3/O3 ·-), (Cl2/Cl2 ·-), (Br2 ·-/2Br-), (NO2 ·/NO2 -), and (CO3 ·-/CO3 2-). 

  • 2.
    Barreiro Fidalgo, Alexandre
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Radiation induced dissolution of (U, Gd)O-2 pellets in aqueous solution - A comparison to standard UO2 pellets2019In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 514, p. 216-223Article in journal (Refereed)
    Abstract [en]

    The behavior of spent nuclear fuel exposed to groundwater is crucial in the safety assessment of a deep geological repository for spent nuclear fuel. For this reason, leaching experiments on spent nuclear fuel as well as non-radioactive analogues have been conducted for several decades. Although the processes involved can be considered to be fairly well understood, there is a need for further experimental studies whenever new fuel types are introduced. Fuels with burnable absorbers are now in use but very little is known about their behavior under repository conditions. In this work, the impact of burnable absorbers doping (Gd, 3-8%wt.) on the oxidative dissolution of UO2 in an aqueous system was studied in H2O2 and gamma-irradiation induced dissolution experiments. The results showed a significant decrease in uranium dissolution and lower reactivity towards H2O2 for (U,Gd)O-2 pellets compared to standard UO2. The resulting decrease in the final oxidative dissolution yield was mainly attributed to decreased redox reactivity of the UO2-matrix upon doping. The results of the gamma radiation exposures display an even larger effect of Gd-doping. These findings indicate that other processes are involved in the radiation-induced dissolution of Gd-doped UO2 compared to pure UO2. 

  • 3.
    Bernhem, Kristoffer
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Blom, H.
    KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Brismar, Hjalmar
    KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Engineering Sciences (SCI), Applied Physics.
    Quantification of endogenous and exogenous protein expressions of Na,K-ATPase with super-resolution PALM/STORM imaging2018In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 13, no 4, article id e0195825Article in journal (Refereed)
    Abstract [en]

    Transient transfection of fluorescent fusion proteins is a key enabling technology in fluorescent microscopy to spatio-temporally map cellular protein distributions. Transient transfection of proteins may however bypass normal regulation of expression, leading to overexpression artefacts like misallocations and excess amounts. In this study we investigate the use of STORM and PALM microscopy to quantitatively monitor endogenous and exogenous protein expression. Through incorporation of an N-terminal hemagglutinin epitope to a mMaple3 fused Na,K-ATPase (α1 isoform), we analyze the spatial and quantitative changes of plasma membrane Na,K-ATPase localization during competitive transient expression. Quantification of plasma membrane protein density revealed a time dependent increase of Na,K-ATPase, but no increase in size of protein clusters. Results show that after 41h transfection, the total plasma membrane density of Na,K-ATPase increased by 63% while the endogenous contribution was reduced by 16%. © 2018 Bernhem et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

  • 4.
    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, 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.

  • 5.
    Brinck, Tore
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Stenlid, Joakim H.
    Stockholm Univ, AlbaNova Univ Ctr, Dept Phys, SE-10691 Stockholm, Sweden..
    The Molecular Surface Property Approach: A Guide to Chemical Interactions in Chemistry, Medicine, and Material Science2019In: ADVANCED THEORY AND SIMULATIONS, ISSN 2513-0390, Vol. 2, no 1, article id 1800149Article in journal (Refereed)
    Abstract [en]

    The current status of the molecular surface property approach (MSPA) and its application for analysis and prediction of intermolecular interactions, including chemical reactivity, are reviewed. The MSPA allows for identification and characterization of all potential interaction sites of a molecule or nanoparticle by the computation of one or more molecular properties on an electronic isodensity surface. A wide range of interactions can be analyzed by three properties, which are well-defined within Kohn-Sham density functional theory. These are the electrostatic potential, the average local ionization energy, and the local electron attachment energy. The latter two do not only reflect the electrostatic contribution to a chemical interaction, but also the contributions from polarization and charge transfer. It is demonstrated that the MSPA has a high predictive capacity for non-covalent interactions, for example, hydrogen and halogen bonding, as well as organic substitution and addition reactions. The latter results open u p applications within drug design and medicinal chemistry. The application of MSPA has recently been extended to nanoparticles and extended surfaces of metals and metal oxides. In particular, nanostructural effects on the catalytic properties of noble metals are rationalized. The potential for using MSPA in rational design of heterogeneous catalysts is discussed.

  • 6.
    Bronken, Ida Antonia Tank
    et al.
    Natl Museum Art Architecture & Design, Dept Collect Management, Holmenkollveien 37b, N-0376 Oslo, Norway..
    Boon, Jaap J.
    JAAP Enterprise Art Sci Studies, Amsterdam, Netherlands..
    Corkery, Robert
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Steindal, Calin Constantin
    Univ Oslo, Museum Cultural Hist, Oslo, Norway..
    Changing surface features, weeping and metal soap formation in paintings by Karel Appel and Asger Jorn from 1946-19712019In: Journal of Cultural Heritage, ISSN 1296-2074, E-ISSN 1778-3674, Vol. 35, p. 279-287Article in journal (Refereed)
    Abstract [en]

    This paper presents results from ongoing investigations of soft and dripping oil paint in art works by CoBrA's Karel Appel (1921-2006) and Asger Jorn (1914-1973). The work is part of the PhD-project Investigation of soft and dripping paint in paintings from 1946-1971 where twenty-four paintings are being investigated. The paintings were chosen to represent a large variety of conditions: some with slightly soft and mainly stable paints, and others with deforming and dripping paints. All paintings chosen had some paint with uneven fluorescence emitted from specific paint colours. Earlier studies have shown that fluorescence can be an indicator of softening paint. The softening paints and drips on the surface of some of these paintings show similar polarity features with mid-chain functionalized stearic acids and azelaic acid moieties. Our findings show there are several physical and chemical alterations within one degradation symptom that have to be understood when conservation treatments are considered in the future.

  • 7.
    Cifelli, M.
    et al.
    Univ Pisa, Dipartimento Chim & Chim Ind, I-56124 Pisa, Italy..
    Domenici, V.
    Univ Pisa, Dipartimento Chim & Chim Ind, I-56124 Pisa, Italy..
    Chizhik, V. I.
    St Petersburg State Univ, Dept Phys, St Petersburg 199034, Russia..
    Dvinskikh, Sergey
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. St Petersburg State Univ, Lab Biomol NMR, St Petersburg 199034, Russia.
    N-15-C-13 Dipole Couplings in Smectic Mesophase of a Thermotropic Ionic Liquid2018In: Applied Magnetic Resonance, ISSN 0937-9347, E-ISSN 1613-7507, Vol. 49, no 6, p. 553-562Article in journal (Refereed)
    Abstract [en]

    Unique combination of ionic conductivity and anisotropic physical properties in ionic liquid crystals leads to new dynamic properties exploited in modern technological applications. Structural and dynamics information at atomic level for molecules and ions in mesophases can be obtained by nuclear magnetic resonance (NMR) spectroscopy through the measurements of dipole-dipole spin couplings. While C-13-H-1 and N-15-H-1 dipolar NMR spectra can be routinely acquired in samples with natural isotopic abundance, recording N-15-C-13 dipolar NMR spectra is challenging because of the unfavourable combination of two rare isotopes. In the present study, an approach to measure N-15-C-13 dipole-dipole NMR spectra in static liquid crystalline samples with natural abundance is introduced. We demonstrate that well-resolved spectra can be recorded within 10 h of experimental time using a conventional NMR probe and a moderately strong magnetic field. The technique is applied to a thermotropic smectic mesophase formed by an ionic liquid with imidazolium-based organic cation.

  • 8.
    Cuartero, Maria
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Crespo, Gaston A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    All-solid-state potentiometric sensors: A new wave for in situ aquatic research2018In: Current Opinion in Electrochemistry, ISSN 2451-9103, Vol. 10, p. 98-106Article in journal (Refereed)
    Abstract [en]

    Over the last few years, all-solid-state potentiometric ion-selective sensors have demonstrated a huge potential for environmental water analysis. Beyond the excellent analytical performances exhibited in benchtop conditions for the detection of important targets (e.g. pH, species relevant to the carbon and nitrogen cycles, trace metals), the challenge now lies in bringing those sensors to in situ format and obtaining valuable chemical information directly in the field while minimizing or avoiding the need for sampling. Technically speaking, the instrumentation for potentiometric assessment is extremely simple, low cost and requires minimal space. In addition, the all-solid-state configuration seems ideal to fabricate miniaturized sensors with sufficient analytical performance to detect certain ions in water resources. Herein, we highlight the power of all-solid-state potentiometric sensors applied to environmental water analysis providing a threefold overview: (i) the recent materials used in the fabrication of all-solid-state polymeric membrane electrodes, both the solid contact and ion-selective membrane; (ii) a collection of the main targets explored during the last 5 years; and (iii) examples of the most recent and relevant in situ applications employing submersible equipment. Throughout the review, issues such as ‘What are the real implications of all-solid-state membrane electrodes in the environmental field?’ and ‘To what extent has the effort in developing new sensors over time been well-exploited?’ are addressed. Convincingly, all-solid-state potentiometric sensors are positioning as a unique in situ interface providing real-time data that allow for an understanding of ongoing biogeochemical processes and possible anthropogenic activities implications.

  • 9.
    Cuartero, Maria
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Crespo, Gaston A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Using Potentiometric Electrodes Based on Nonselective Polymeric Membranes as Potential Universal Detectors for Ion Chromatography: Investigating an Original Research Problem from an Inquiry-Based-Learning Perspective2018In: Journal of Chemical Education, ISSN 0021-9584, E-ISSN 1938-1328, Vol. 95, no 12, p. 2172-2181Article in journal (Refereed)
    Abstract [en]

    Because traditional laboratory practices in advanced chemistry education are being replaced by inquiry based approaches, we present herein a new laboratory activity based on a small research project that was designed and executed by students. The laboratory project aims at answering a well-defined research question: how far can potentiometric electrodes based on nonselective polymeric membranes be used as universal detectors in ion chromatography (IC)? Hence, the experiments were designed and conducted to explore the analytical performances of potentiometric electrodes based on different commercial membranes that are typically used in electrodialysis. The nonselective behavior shown by the electrodes permits a critical evaluation of their further implementation as a universal detector of anions in regular IC. Thus, the students were able to integrate a nonselective potentiometric sensor to analyze several anions in flow mode, mimicking the signal that is to be obtained using such electrodes as an IC detector. The proposed practice covers different pedagogical purposes: (i) to develop competence toward "thinking like a scientist" through reflective teaching; (ii) to promote argumentation skills and critical decision making; (iii) to improve students' research-planning and experimental-design skills; (iv) to refresh conceptual knowledge about analytical detectors, which typically goes unnoticed in laboratory practices; and (v) to reinforce students' knowledge about the basis of potentiometry. Furthermore, the present document may serve as an easy guide to develop other laboratory practices based on potentiometric sensors.

  • 10.
    Dai, Jing
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. KTH Royal Inst Technol, Div Appl Phys Chem, Dept Chem, SE-10044 Stockholm, Sweden..
    Ferreira Fernandes, Ricardo Manuel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. KTH Royal Inst Technol, Div Appl Phys Chem, Dept Chem, SE-10044 Stockholm, Sweden.;Univ Porto, CIQUP, Dept Chem & Biochem, Fac Sci, P-4169007 Porto, Portugal..
    Regev, Oren
    Ben Gurion Univ Negev, Dept Chem Engn, IL-84105 Beer Sheva, Israel.;Ben Gurion Univ Negev, Ilse Katz Inst Nanotechnol, IL-84105 Beer Sheva, Israel..
    Marques, Eduardo F.
    Univ Porto, CIQUP, Dept Chem & Biochem, Fac Sci, P-4169007 Porto, Portugal..
    Furo, Istvan
    KTH, School of Chemical Science and Engineering (CHE), Centres, Industrial NMR Centre. KTH Royal Inst Technol, Div Appl Phys Chem, Dept Chem, SE-10044 Stockholm, Sweden..
    Dispersing Carbon Nanotubes in Water with Amphiphiles: Dispersant Adsorption, Kinetics, and Bundle Size Distribution as Defining Factors2018In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, no 42, p. 24386-24393Article in journal (Refereed)
    Abstract [en]

    Debundling and dispersing single-walled carbon nanotubes (SWNTs) is essential for applications, but the process is not well understood. In this work, aqueous SWNT dispersions were produced by sonicating pristine SWNT powder in the presence of an amphiphilic triblock copolymer (Pluronic F127) as dispersant. Upon centrifugation, one obtains a supernatant with suspended individual tubes and thin bundles and a precipitate with large bundles (and impurities). In the supernatant, that constitutes the final dispersion, we determined the dispersed SWNT concentration by thermogravi-metric analysis (TGA) and UV-vis spectroscopy, and the dispersant concentration by NMR The fraction of dispersant adsorbed at the SWNT surface was obtained by H-1 diffusion NMR Sigmoidal dispersion curves recording the concentration of dispersed SWNTs as a function of supernatant dispersant concentration were obtained at different SWNT loadings and sonication times. As SWNT bundles are debundled into smaller and smaller ones, the essential role of the dispersant is to sufficiently quickly cover the freshly exposed surfaces created by shear forces induced during sonication. Primarily kinetic reasons are behind the need for dispersant concentrations required to reach a substantial SWNT concentration. Centrifugation sets the size threshold below which SWNT particles are retained in the dispersion and consequently determines the SWNT concentration as a function of sonication time.

  • 11. Ditta, L. A.
    et al.
    Dahlgren, Björn
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Sabatino, M. A.
    Dispenza, C.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    The role of molecular oxygen in the formation of radiation-engineered multifunctional nanogels2019In: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 114, p. 164-175Article in journal (Refereed)
    Abstract [en]

    Nanogels are very promising biomedical nanodevices. The classic “radiation chemistry-based” approach to synthetize nanogels consists in the irradiation with pulsed electron beams of dilute, N 2 O-saturated, aqueous solutions of water-soluble polymers of the “crosslinking type”. Nanogels with controlled size and properties are produced in a single irradiation step with no recourse to initiators, organic solvents and surfactants. This paper combines experimental syntheses, performed with two e-beam irradiation setups and dose-ranges, starting from poly(N-vinyl pyrrolidone) solutions of various concentrations, both in N 2 O-saturated and air-saturated initial conditions, with the numerical simulations of the radiation chemistry of aqueous solutions of a radical scavanger exposed to the same irradiation conditions used in the experiments. This approach provides a methodology to predict the impact of system and irradiation conditions on the water radiation chemistry, which in turn affect the nanogel features in terms of molecular and physico-chemical properties. In particular, the crucial role of initial and transient concentration of molecular oxygen is revealed. This work also proposes a very simple and effective methodology to quantitatively measure the double bonds formed in the systems from disporportionation and chain scission reactions, competing with inter-/intra-molecular crosslinking.

  • 12.
    Elwinger, Fredrik
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. GE Healthcare Biosci AB, Bjorkgatan 31, SE-75184 Uppsala, Sweden..
    Wernersson, Jonny
    GE Healthcare Biosci AB, Bjorkgatan 31, SE-75184 Uppsala, Sweden..
    Furo, Istvan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. GE Healthcare Biosci AB, Bjorkgatan 31, SE-75184 Uppsala, Sweden..
    Quantifying Size Exclusion by Diffusion NMR: A Versatile Method to Measure Pore Access and Pore Size2018In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 90, no 19, p. 11431-11438Article in journal (Refereed)
    Abstract [en]

    Size-exclusion quantification NMR spectroscopy (SEQNMR) is introduced for measuring equilibrium distribution coefficients, K-eq, in porous media. The porous medium is equilibrated with a polydisperse polymer solution. The original bulk polymer solution and the polymer solution after equilibration but in the absence of the porous medium are analyzed by NMR diffusion experiments. The joint evaluation of the two diffusion attenuation curves under suitable constraints provides the extent by which polymer fractions of particular size were depleted from the solution by pore access. This procedure yields K-eq versus polymer probe size, the selectivity curve that in turn can provide the pore size and its distribution. Simulations probe the performance of the method that is demonstrated experimentally in chromatographic media using dextran polymers. SEQ-NMR and inverse size- exclusion chromatography (ISEC) yield selectivity curves that virtually coincide. Crucial advantages with SEQ-NMR, such as versatility with regard to both the polymer used and porous system explored, high speed, potential for automation, and small required sample volume, are discussed.

  • 13.
    Ferreira Fernandes, Ricardo Manuel
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. Univ Porto, Dept Chem & Biochem, CIQUP, Fac Sci, P-4169007 Porto, Portugal..
    Dai, Jing
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Regev, Oren
    Ben Gurion Univ Negev, Dept Chem Engn, IL-84105 Beer Sheva, Israel.;Ben Gurion Univ Negev, Ilse Katz Inst Nanotechnol, IL-84105 Beer Sheva, Israel..
    Marques, Eduardo F.
    Univ Porto, Dept Chem & Biochem, CIQUP, Fac Sci, P-4169007 Porto, Portugal..
    Furo, Istvan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Block Copolymers as Dispersants for Single-Walled Carbon Nanotubes: Modes of Surface Attachment and Role of Block Polydispersity2018In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 34, no 45, p. 13672-13679Article in journal (Refereed)
    Abstract [en]

    When using amphiphilic polymers to exfoliate and disperse carbon nanotubes in water, the balance between the hydrophobic and hydrophilic moieties is critical and nontrivial. Here, we investigate the mode of surface attachment of a triblock copolymer, Pluronics F127, composed of a central hydrophobic polypropylene oxide block flanked by hydrophilic polyethylene oxide blocks, onto single-walled carbon nanotubes (SWNTs). Crucially, we analyze the composition in dispersant of both the as-obtained dispersion (the supernatant) and the precipitate-containing undispersed materials. For this, we combine the carefully obtained data from H-1 NMR peak intensities and self-diffusion and thermogravimetric analysis. The molecular motions behind the observed NMR features are clarified. We find that the hydrophobic blocks attach to the dispersed SWNT surface and remain significantly immobilized leading to H-1 NMR signal loss. On the other hand, the hydrophilic blocks remain highly mobile and thus readily detectable by NMR. The dispersant is shown to possess significant block polydispersity that has a large effect on dispersibility. Polymers with large hydrophobic blocks adsorb on the surface of the carbonaceous particles that precipitate, indicating that although a larger hydrophobic block is good for enhancing adsorption, it may be less effective in dispersing the tubes. A model is also proposed that consistently explains our observations in SWNT dispersions and some contradicting findings obtained previously in carbon nanohorn dispersions. Overall, our findings help elucidating the molecular picture of the dispersion process for SWNTs and are of interest when looking for more effective (i.e., well-balanced) polymeric dispersants.

  • 14.
    Gustafsson, Camilla
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Vassiliev, Serguei
    Department of Biological Sciences, Brock University, Ontario, Canada.
    Kürten, Charlotte
    KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Syrén, Per-Olof
    KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    Brinck, Tore
    MD Simulations Reveal Complex Water Paths in Squalene–Hopene Cyclase: Tunnel-Obstructing Mutations Increase the Flow of Water in the Active Site2017In: ACS Omega, ISSN 2470-1343, Vol. 2, no 11, p. 8495-8506Article in journal (Refereed)
    Abstract [en]

    Squalene–hopene cyclase catalyzes the cyclization of squalene to hopanoids. A previous study has identified a network of tunnels in the protein, where water molecules have been indicated to move. Blocking these tunnels by site-directed mutagenesis was found to change the activation entropy of the catalytic reaction from positive to negative with a concomitant lowering of the activation enthalpy. As a consequence, some variants are faster and others are slower than the wild type (wt) in vitro under optimal reaction conditions for the wt. In this study, molecular dynamics (MD) simulations have been performed for the wt and the variants to investigate how the mutations affect the protein structure and the water flow in the enzyme, hypothetically influencing the activation parameters. Interestingly, the tunnel-obstructing variants are associated with an increased flow of water in the active site, particularly close to the catalytic residue Asp376. MD simulations with the substrate present in the active site indicate that the distance for the rate-determining proton transfer between Asp376 and the substrate is longer in the tunnel-obstructing protein variants than in the wt. On the basis of the previous experimental results and the current MD results, we propose that the tunnel-obstructing variants, at least partly, could operate by a different catalytic mechanism, where the proton transfer may have contributions from a Grotthuss-like mechanism.

  • 15.
    Hao, Yan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Yang, Wenxing
    Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, SE-75120 Uppsala, Sweden.;Emory Univ, Dept Chem, 1515 Dickey Dr NE, Atlanta, GA 30322 USA..
    Karlsson, Karl Martin
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Cong, Jiayan
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Wang, Shihuai
    Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, SE-75120 Uppsala, Sweden..
    Lo, Xing
    East China Univ Sci & Technol, Inst Fine Chem, Sch Chem & Mol Engn, Key Lab Adv Mat, Shanghai 200237, Peoples R China..
    Xu, Bo
    Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, SE-75120 Uppsala, Sweden..
    Hua, Jianli
    East China Univ Sci & Technol, Inst Fine Chem, Sch Chem & Mol Engn, Key Lab Adv Mat, Shanghai 200237, Peoples R China..
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Boschloo, Gerrit
    Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, SE-75120 Uppsala, Sweden..
    Efficient Dye-Sensitized Solar Cells with Voltages Exceeding 1 V through Exploring Tris(4-alkoxyphenyl)amine Mediators in Combination with the Tris(bipyridine) Cobalt Redox System2018In: ACS ENERGY LETTERS, ISSN 2380-8195, Vol. 3, no 8, p. 1929-1937Article in journal (Refereed)
    Abstract [en]

    Tandem redox electrolytes, prepared by the addition of a tris(p-anisyl)amine mediator into classic tris(bipyridine)cobalt-based electrolytes, demonstrate favorable electron transfer and reduced energy loss in dye-sensitized solar cells. Here, we have successfully explored three tris(4-alkoxyphenyl)-amine mediators with bulky molecular structures and generated more effective tandem redox systems. This series of tandem redox electrolytes rendered solar cells with very high photovoltages exceeding 1 V, which approaches the theoretical voltage limit of tris(bipyridine)cobalt-based electrolytes. Solar cells with power conversion efficiencies of 9.7-11.0% under 1 sun illumination were manufactured. This corresponds to an efficiency improvement of up to 50% as compared to solar cells based on pure tris(bipyridine)cobalt-based electrolytes. The photovoltage increases with increasing steric effects of the tris(4-alkoxyphenyl)amine mediators, which is attributed to a retarded recombination kinetics. These results highlight the importance of structural design for optimized charge transfer at the sensitized semiconductor/electrolyte interface and provide insights for the future development of efficient dye-sensitized solar cells.

  • 16.
    Hedberg, Yolanda
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Dobryden, Illia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Chaudhary, Himanshu
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Wei, Zheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Claesson, Per M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Lendel, Christofer
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Synergistic effects of metal-induced aggregation of human serum albumin2019In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 173, p. 751-758Article in journal (Refereed)
    Abstract [en]

    Exposure to cobalt (Co), chromium (Cr), and nickel (Ni) occurs often via skin contact and from different dental and orthopedic implants. The metal ions bind to proteins, which may induce structural changes and aggregation, with different medical consequences. We investigated human serum albumin (HSA) aggregation in the presence of Co-II, Cr-III, and/or Ni-II ions and/or their nanoparticle precipitates by using scattering, spectroscopic, and imaging techniques, at simulated physiological conditions (phosphate buffered saline - PBS, pH 7.3) using metal salts that did not affect the pH, and at HSA:metal molar ratios of up to 1:8. Co ions formed some solid nano particles in PBS at the investigated conditions, as determined by nanoparticle tracking analysis, but the Cr-III anions and Ni-II ions remained fully soluble. It was found that all metal ions induced HSA aggregation, and this effect was significantly enhanced when a mixture of all three metal ions was present instead of any single type of ion. Thus, the metal ions induce aggregation synergistically. HSA aggregates formed linear structures on a mica surface in the presence of Cr-III ions. A clear tendency of aggregation and linearly aligned aggregates was seen in the presence of all three metal ions. Spectroscopic investigations indicated that the majority of the HSA molecules maintained their alpha helical secondary structure and conformation. This study highlights the importance of synergistic effects of metal ions and/or their precipitates on protein aggregation, which are highly relevant for implant materials and common exposures to metals.

  • 17.
    Hua, Yong
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Liu, Peng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical 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), Chemical Engineering.
    Sun, Licheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Kloo, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Composite Hole-Transport Materials Based on a Metal-Organic Copper Complex and Spiro-OMeTAD for Efficient Perovskite Solar Cells2018In: SOLAR RRL, ISSN 2367-198X, Vol. 2, no 5, article id UNSP 1700073Article in journal (Refereed)
    Abstract [en]

    Spiro-OMeTAD has been the most commonly used hole-transport material in perovskite solar cells. However, this material shows intrinisic drawbacks, such as low hole mobility and conductivity in its pristine form, as well as self-aggregation when deposited as thin film. These are not beneficial properties for efficient hole transport and extraction. In order to address these issues, we have designed a new type of composite hole-transport materials based on a new metal-organic copper complex (CuH) and Spiro-OMeTAD. The incorporation of the molecularly bulky HTM CuH into the Spiro-OMeTAD material efficiently improves the hole mobility and suppresses the aggregation in the Spiro-OMeTAD film. As a result, the conversion efficiencies obtained for perovskite solar cells based on the composite HTM system reached as high as 18.83%, which is superior to solar cells based on the individual hole-transport materials CuH (15.75%) or Spiro-OMeTAD (14.47%) under the same working conditions. These results show that composite HTM systems may constitute an effective strategy to further improve the efficiency of perovskite solar cells.

  • 18. Janosik, T.
    et al.
    Rannug, A.
    Rannug, U.
    Wahlström, N.
    Slätt, Johnny
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Bergman, J.
    Chemistry and Properties of Indolocarbazoles2018In: Chemical Reviews, ISSN 0009-2665, E-ISSN 1520-6890, Vol. 118, no 18, p. 9058-9128Article in journal (Refereed)
    Abstract [en]

    The indolocarbazoles are an important class of nitrogen heterocycles which has evolved significantly in recent years, with numerous studies focusing on their diverse biological effects, or targeting new materials with potential applications in organic electronics. This review aims at providing a broad survey of the chemistry and properties of indolocarbazoles from an interdisciplinary point of view, with particular emphasis on practical synthetic aspects, as well as certain topics which have not been previously accounted for in detail, such as the occurrence, formation, biological activities, and metabolism of indolo[3,2-b]carbazoles. The literature of the past decade forms the basis of the text, which is further supplemented with older key references.

  • 19.
    Johansson, F. O. L.
    et al.
    Uppsala Univ, Dept Phys & Astron, Mol & Condensed Matter Phys, Box 516, SE-75120 Uppsala, Sweden..
    Ivanovic, M.
    Univ Tubingen, Inst Phys & Theoret Chem, Morgenstelle 18, D-72076 Tubingen, Germany..
    Svanstrom, S.
    Uppsala Univ, Dept Phys & Astron, Mol & Condensed Matter Phys, Box 516, SE-75120 Uppsala, Sweden..
    Cappel, Ute B.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. Uppsala Univ, Dept Phys & Astron, Mol & Condensed Matter Phys, Box 516, SE-75120 Uppsala, Sweden.
    Peisert, H.
    Univ Tubingen, Inst Phys & Theoret Chem, Morgenstelle 18, D-72076 Tubingen, Germany..
    Chasse, T.
    Univ Tubingen, Inst Phys & Theoret Chem, Morgenstelle 18, D-72076 Tubingen, Germany..
    Lindblad, A.
    Uppsala Univ, Dept Phys & Astron, Mol & Condensed Matter Phys, Box 516, SE-75120 Uppsala, Sweden..
    Femtosecond and Attosecond Electron-Transfer Dynamics in PCPDTBT:PCBM Bulk Heterojunctions2018In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, no 24, p. 12605-12614Article in journal (Refereed)
    Abstract [en]

    Charge separation efficiency is a crucial parameter for photovoltaic devices-polymers consisting of alternating electron-rich and electron-deficient parts can achieve high such efficiencies, for instance, together with a fullerene electron acceptor. This offers a viable path toward solar cells with organic bulk heterojunctions. Here, we measured the charge-transfer times in the femtosecond and attosecond regimes via the decay of sulfur is X-ray core excited states (with the core-hole clock method) in blends of a low-band gap polymer {PCPDTBT [poly[2,6-(4,4-bis (2-ethylhexyl)-4H-cyclopenta [2,1-b;3,4-1/1 dithiophene)-alt-4,7- (2,1,3-benzothiadiazole)]]} consisting of a cyclopentadithiophene electron-rich part and a benzothiadiazole electron-deficient part. The constituting parts of the bulk heterojunction were varied by adding the fullerene derivative PCBM ([6,6]-phenyl-C-61-butyric acid methyl ester) (weight ratio of polymer/PCBM as 1:0, 1:1, 1:2, and 1:3). For low-energy excitations, the charge-transfer time varies to the largest extent for the thiophene donor part. The charge-transfer time in the 1:2 blend is reduced by 86% compared to that of pristine PCPDTBT. At higher energy excitations, the charge-transfer time does not vary with the chemical environment, as this regime is dominated by intramolecular conduction that yields ultrafast charge-transfer times for all blends, approaching 170 as. We thus demonstrate that the core-hole clock method applied to a series with changing composition can give information about local electron dynamics (with chemical specificity) at interfaces between the constituting parts the crucial part of a bulk heterojunction where the initial charge separation occurs.

  • 20.
    Josefsson, Leila
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Cronhamn, Melker
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Ekman, Malin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Widehammar, Hugo
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Emmer, Åsa
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Lendel, Christofer
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Structural basis for the formation of soy protein nanofibrils2019In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 11, p. 6310-6319Article in journal (Refereed)
    Abstract [en]

    Amyloid-like protein nanofibrils (PNFs) can assemble from a range of different proteins including disease-associated proteins, functional amyloid proteins and several proteins for which the PNFs are neither related to disease nor function. We here examined the core building blocks of PNFs formed by soy proteins. Fibril formation at pH 2 and 90 degrees C is coupled to peptide hydrolysis which allows isolation of the PNF-forming peptides and identification of them by mass spectrometry. We found five peptides that constitute the main building blocks in soy PNFs, three of them from the protein b-conglycinin and two from the protein glycinin. The abilities of these peptides to form PNFs were addressed by amyloid prediction software and by PNF formation of the corresponding synthetic peptides. Analysis of the structural context in the native soy proteins revealed two structural motifs for the PNF-forming peptides: (i) so-called b-arches and (ii) helical segments involved in quaternary structure contacts. However, the results suggest that neither the native structural motifs nor the protein of origin defines the morphology of the PNFs formed from soy protein isolate.

  • 21.
    Kamada, Ayaka
    et al.
    Univ Tokyo, Dept Bioengn, Tokyo, Japan..
    Mittal, Nitesh
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH Royal Inst Technol, KTH Mech, Stockholm, Sweden..
    Söderberg, Daniel
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH Royal Inst Technol, KTH Mech, Stockholm, Sweden..
    Lendel, Christofer
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. KTH Royal Inst Technol, Dept Chem, Stockholm, Sweden..
    Lundell, Fredrik
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH Royal Inst Technol, KTH Mech, Stockholm, Sweden..
    Assembly mechanism of nanostructured whey protein filaments2016In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 252Article in journal (Other academic)
  • 22.
    Leandri, V.
    et al.
    Uppsala Univ, Dept Chem, Angstrom Lab, S-75120 Uppsala, Sweden..
    Yang, W.
    Uppsala Univ, Dept Chem, Angstrom Lab, S-75120 Uppsala, Sweden.;Imperial Coll London, Dept Chem, London SW7 2AZ, England..
    Gardner, James M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Boschloo, G.
    Uppsala Univ, Dept Chem, Angstrom Lab, S-75120 Uppsala, Sweden..
    Ott, S.
    Uppsala Univ, Dept Chem, Angstrom Lab, S-75120 Uppsala, Sweden..
    Rapid Microwave-Assisted Self-Assembly of a Carboxylic-Acid-Terminated Dye on a TiO2 Photoanode2018In: ACS APPLIED ENERGY MATERIALS, ISSN 2574-0962, Vol. 1, no 1, p. 202-210Article in journal (Refereed)
    Abstract [en]

    Self-assembly of carboxylic-acid-functionalized dyes on mesoporous, anatase TiO2 is at the heart of dye-sensitized solar cells (DSSCs). However, the process often requires 6-20 h of electrode immersion at room temperature in the dye-bath solutions. Here, we introduce a new, rapid microwave-assisted sensitization technique (MINAS), which significantly accelerates the sensitization process and yields high-quality, self-assembled films of an organic dye within 5 min. Targeted experiments show that the effects of the microwave radiation cannot be explained purely on the basis of the thermal component. The interaction of the microwave radiation with the conductive fluorine-doped tin oxide (FTO) electrical contact is a key aspect to consider and a unique feature of MWAS that is the likely cause for producing rapid self-assembly of the dye on the surface.

  • 23.
    Leandri, Valentina
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Daniel, Quentin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Chen, Hong
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. 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.
    Kloo, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Electronic and Structural Effects of Inner Sphere Coordination of Chloride to a Homoleptic Copper(II) Diimine Complex2018In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 57, no 8, p. 4556-4562Article in journal (Refereed)
    Abstract [en]

    The reaction of CuCl2 with 2,9-dimethyl-1,10-phenanthroline (dmp) does not lead to the formation of [Cu(dmp)(2)](Cl)(2) but instead to [Cu(dmp)(2)Cl]Cl, a 5-coordinated complex, in which one chloride is directly coordinated to the metal center. Attempts at removing the coordinated chloride by changing the counterion by metathesis were unsuccessful and resulted only in the exchange of the noncoordinated chloride, as confirmed from a crystal structure analysis. Complex [Cu-(dmp)(2)Cl]PF6 exhibits a reversible cyclic voltammogram characterized by a significant peak splitting between the reductive and oxidative waves (0.85 and 0.60 V vs NHE, respectively), with a half-wave potential E-1/2 = 0.73 V vs NHE. When reduced electrochemically, the complex does not convert into [Cu(dmp)(2)](+), as one may expect. Instead, [Cu(dmp)(2)](+) is isolated as a product when the reduction of [Cu(dmp)(2)Cl]PF6 is performed with L-ascorbic acid, as confirmed by electrochemistry, NMR spectroscopy, and diffractometry. [Cu(dmp)(2)](2+) complexes can be synthesized starting from Cu(II) salts with weakly and noncoordinating counterions, such as perchlorate. Growth of [Cu(dmp)(2)](ClO4)(2) crystals in acetonitrile results in a 5-coordinated complex, [Cu(dmp)(2)(CH3CN)](ClO4)(2), in which a solvent molecule is coordinated to the metal center. However, solvent coordination is associated with a dynamic decoordination-coordination behavior upon reduction and oxidation. Hence, the cyclic voltammogram of [Cu(dmp)(2)(CH3CN)](2+) is identical to the one of [Cu(dmp)(2)](+), if the measurements are performed in acetonitrile. The current results show that halide ions in precursors to Cu(II) metal-organic coordination compound synthesis, and most likely also other multivalent coordination centers, are not readily exchanged when exposed to presumed strongly binding and chelating ligand, and thus special care needs to be taken with respect to product characterization.

  • 24.
    Leandri, Valentina
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Liu, Peng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Sadollahkhani, Azar
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Safdari, Majid
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Kloo, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Gardner, James M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Excited-State Dynamics of [Ru(bpy)(3)](2+) Thin Films on Sensitized TiO2 and ZrO22019In: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 20, no 4, p. 618-626Article in journal (Refereed)
    Abstract [en]

    The excited state dynamics of Tris(2,2 '-bipyridine)ruthenium(II) hexafluorophosphate, [Ru(bpy)(3)(PF6)(2)], was investigated on the surface of bare and sensitized TiO2 and ZrO2 films. The organic dyes LEG4 and MKA253 were selected as sensitizers. A Stern-Volmer plot of LEG4-sensitized TiO2 substrates with a spin-coated [Ru(bpy)(3)(PF6)(2)] layer on top shows considerable quenching of the emission of the latter. Interestingly, time-resolved emission spectroscopy reveals the presence of a fast-decay time component (25 +/- 5 ns), which is absent when the anatase TiO2 semiconductor is replaced by ZrO2. It should be specified that the positive redox potential of the ruthenium complex prevents electron transfer from the [Ru(bpy)(3)(PF6)(2)] ground state into the oxidized sensitizer. Therefore, we speculate that the fast-decay time component observed stems from excited-state electron transfer from [Ru(bpy)(3)(PF6)(2)] to the oxidized sensitizer. Solid-state dye sensitized solar cells (ssDSSCs) employing MKA253 and LEG4 dyes, with [Ru(bpy)(3)(PF6)(2)] as a hole-transporting material (HTM), exhibit 1.2 % and 1.1 % power conversion efficiency, respectively. This result illustrates the possibility of the hypothesized excited-state electron transfer.

  • 25.
    Liljenberg, Magnus
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Halldin Stenlid, Joakim
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Brinck, Tore
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Mechanism and regioselectivity of electrophilic aromatic nitration in solution: the validity of the transition state approach2018In: Journal of Molecular Modeling, ISSN 1610-2940, E-ISSN 0948-5023, Vol. 24, no 1, article id 15Article in journal (Refereed)
    Abstract [en]

    The potential energy surfaces in gas phase and in aqueous solution for the nitration of benzene, chlorobenzene, and phenol have been elucidated with density functional theory at theM06-2X/6-311G(d,p) level combined with the polarizable continuum solvent model (PCM). Three reaction intermediates have been identified along both surfaces: the unoriented pi-complex (I), the oriented reaction complex (II), and the sigma-complex (III). In order to obtain quantitatively reliable results for positional selectivity and for modeling the expulsion of the proton, it is crucial to take solvent effects into consideration. The results are in agreement with Olah's conclusion from over 40 years ago that the transition state leading to (II) is the rate-determining step in activated cases, while it is the one leading to (III) for deactivated cases. The simplified reactivity approach of using the free energy for the formation of (III) as a model of the rate-determining transition state has previously been shown to be very successful for halogenations, but problematic for nitrations. These observations are rationalized with the geometric and energetic resemblance, and lack of resemblance respectively, between (III) and the corresponding rate determining transition state. At this level of theory, neither the sigma-complex (III) nor the reaction complex (II) can be used to accurately model the rate-determining transition state for nitrations.

  • 26. Lindman, Björn
    et al.
    Stilbs, Peter
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Molecular diffusion in microemulsions2018In: Microemulsions: Structure and Dynamics, CRC Press, 2018, p. 119-152Chapter in book (Other academic)
    Abstract [en]

    The interest in studies of diffusional processes in microemulsions has grown rapidly during the past few years. The reasons are an increased number of available techniques providing easily interpretable data and the realization that self-diffusion data give unique information on the molecular organization and structure of microemulsions. Furthermore, many current and potential applications of microemulsions are dependent on molecular transport over macroscopic distances.

  • 27.
    Li, Zhuofeng
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Soroka, Inna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Min, Fanyi
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    pH-Control as a way to fine-tune the Cu/Cu2O ratio in radiation induced synthesis of Cu2O particles2018In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 47, no 45, p. 16139-16144Article in journal (Refereed)
    Abstract [en]

    In this work we have optimized the -radiation induced synthesis of Cu-Cu2O particles from aqueous CuSO4 solution by investigating the effect of pH. The obtained precipitate was analyzed by XRD and SEM techniques. The results indicated that at solution pH lower than 3.75, quasi-spherical Cu agglomerates can be formed while at pH higher than 4.40 only octahedron-shaped Cu2O particles are produced. At solution pH in the range from 3.75 to 4.40, a Cu-Cu2O mixture is produced. It was found that the relative amount of Cu2O in the Cu-Cu2O precipitate increases with pH in the studied range. The influence of solution pH on the Cu/Cu2O ratios in the product can be explained on the basis of pH-dependent competition kinetics between the reactions leading to either Cu or Cu2O formation. As a consequence, the composition and morphology of the Cu-Cu2O precipitate can be tuned by controlling pH of the aqueous CuSO4 solution during the -radiation induced synthesis.

  • 28.
    Maier, Annika Carolin
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Benarosch, A.
    El Jamal, Ghada
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Radiation induced dissolution of U 3 Si 2 - A potential accident tolerant fuel2019In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 517, p. 263-267Article in journal (Refereed)
    Abstract [en]

    To assess the integrity of the accident tolerant fuel candidate U 3 Si 2 under geological repository conditions, the kinetics of γ-radiation- and H 2 O 2 - induced oxidative dissolution was studied. The experiments were performed in aqueous solutions containing 10 mM HCO 3 − and in solutions without added HCO 3 − . The same experiments were also performed on UO 2 for comparison. All experiments were performed using powder suspensions. The experiments show that U 3 Si 2 is less than one order of magnitude more reactive towards H 2 O 2 than is UO 2 . The dissolution yield of U 3 Si 2 slightly exceeds the theoretical yield (23%). In experiments with consecutive additions of H 2 O 2 in HCO 3 − solutions, the reactivity remains constant implying that no significant amount of a secondary phase is formed on the U 3 Si 2 surface. The dissolution of Si closely follows that of U in HCO 3 − solution. In solutions without added HCO 3 − the reactivity towards H 2 O 2 is reduced by a factor less than 2. The dissolution is slightly slower than in HCO 3 − containing solutions but precipitation of U is observed after some time. The results of consecutive additions of H 2 O 2 to the HCO 3 − free system shows that the reactivity is decreasing for every addition. This indicates that a secondary phase is formed. XRD shows that the secondary phase is studtite. The irradiation experiments show that the surface area normalized radiation chemical yields for uranium dissolution for U 3 Si 2 and UO 2 in HCO 3 − solution differ by a factor 5–10 in favour of UO 2 . This difference can largely be attributed to the difference in dissolution yield.

  • 29. Matveev, V. V.
    et al.
    Markelov, D. A.
    Dvinskikh, Sergey
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Shishkin, A. N.
    Tyutyukin, K. V.
    Penkova, A. V.
    Tatarinova, E. A.
    Ignat'Eva, G. M.
    Milenin, S. A.
    Investigation of Melts of Polybutylcarbosilane Dendrimers by 1H NMR Spectroscopy2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, no 1, article id 13710Article in journal (Refereed)
    Abstract [en]

    Melts of polybutylcarbosilane (PBC) dendrimers from third (G3) up to sixth (G6) generations are investigated by 1H NMR spectroscopy in a wide temperature range up to 493 K. At room temperature, NMR spectra of G3-G5 dendrimers exhibit resolved, solution-like spectra ("liquid" phase). In contrast, the spectrum of the G6 dendrimer is characterized by a single unresolved broad line at whole temperature range, which supports the presence of an anomalous phase state of G6 at temperatures higher than glass transition temperature. For the first time, an unexpected transition of G5 dendrimer from a molecular liquid state to an anomalous state/phase upon temperature increase has been detected using NMR data. Specifically, an additional wide background line appears in the G5 spectrum above 473 K, and this line corresponds to a G5 state characterized by restricted molecular mobility, i.e., a state similar to the "anomalous" phase of G6 melt. The fraction of the G5 dendrimers in "anomalous" phase at 493 K is approximately 40%. Analysis of the spectral shapes suggests that changes in the G5 dendrimers are reversible with temperature.

  • 30.
    Mikkonen, Saara
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. Univ Bern, Inst Infect Dis, Clin Pharmacol Lab, Bern, Switzerland..
    Caslayskal, Jitka
    Univ Bern, Inst Infect Dis, Clin Pharmacol Lab, Bern, Switzerland..
    Gebauer, Petr
    Czech Acad Sci, Inst Analyt Chem, Brno, Czech Republic..
    Thormanni, Wolfgang
    Univ Bern, Inst Infect Dis, Clin Pharmacol Lab, Bern, Switzerland..
    Inverse cationic ITP for separation of methadone enantiomers with sulfated beta-cyclodextrin as chiral selector2019In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 40, no 5, p. 659-667Article in journal (Refereed)
    Abstract [en]

    Chiral ITP of the weak base methadone using inverse cationic configurations with H+ as leading component and multiple isomer sulfated beta-CD (S-beta-CD) as leading electrolyte (LE) additive, has been studied utilizing dynamic computer simulation, a calculation model based on steady-state values of the ITP zones, and capillary ITP. By varying the amount of acidic S-beta-CD in the LE composed of 3-morpholino-2-hydroxypropanesulfonic acid and the chiral selector, and employing glycylglycine as terminating electrolyte (TE), inverse cationic ITP provides systems in which either both enantiomers, only the enantiomer with weaker complexation, or none of the two enantiomers form cationic ITP zones. For the configuration studied, the data reveal that only S-methadone migrates isotachophoretically when the S-beta-CD concentration in the LE is between about 0.484 and 1.113 mM. Under these conditions, R-methadone migrates zone electrophoretically in the TE. An S-beta-CD concentration between about 0.070 and 0.484 mM results in both S- and R-methadone forming ITP zones. With >1.113 mM and < about 0.050 mM of S-beta-CD in the LE both enantiomers are migrating within the TE and LE, respectively. Chiral inverse cationic ITP with acidic S-beta-CD in the LE is demonstrated to permit selective ITP trapping and concentration of the less interacting enantiomer of a weak base.

  • 31. Nadiv, R.
    et al.
    Fernandes, Ricardo M. F.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Ochbaum, G.
    Dai, Jing
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Buzaglo, M.
    Varenik, M.
    Biton, R.
    Furo, Istvan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Regev, O.
    Polymer nanocomposites: Insights on rheology, percolation and molecular mobility2018In: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 153, p. 52-60Article in journal (Refereed)
    Abstract [en]

    The integration of carbon nanotubes (CNTs) into a polymer matrix strongly affects the rheological behavior that in turn may hamper the overall performance of the resulting composite. Research in this topic has focused on bulk rheological properties, while here we employ NMR diffusion experiments to explore the mobility (diffusivity) of epoxy molecules when loaded with CNTs. Rheology and light microscopy indicate percolation of CNT aggregates. Those aggregates cage a substantial amount of epoxy molecules while small angle X-ray scattering indicates some rearrangement of epoxy molecules in the vicinity of the nanotubes. NMR diffusion experiments distinguish between the slow diffusion of the caged molecules and that of the free ones, and relate the fraction of the former to the macroscopic system viscosity. The demonstrated surface-induced slowing-down of diffusion is attributed to strong intermolecular π-π interactions among the epoxy molecules, and between them and the CNT surface. These findings demonstrate the utility of NMR diffusion experiments as an additional method applied to nanocomposites. 

  • 32.
    Niga, Petru
    et al.
    RISE Res Inst Sweden Chem Mat & Surfaces, Box 5607, SE-11486 Stockholm, Sweden..
    Hansson-Mille, Petra M.
    RISE Res Inst Sweden Chem Mat & Surfaces, Box 5607, SE-11486 Stockholm, Sweden..
    Swerin, Agne
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Claesson, Per M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Schoelkopf, Joachim
    Omya Int AG, Baslerstr 42, CH-4665 Oftringen, Switzerland..
    Gane, Patrick A. C.
    Omya Int AG, Baslerstr 42, CH-4665 Oftringen, Switzerland.;Aalto Univ, Sch Chem Technol, Dept Bioprod & Biosyst, FI-00076 Helsinki, Finland..
    Dai, Jing
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Furo, Istvan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Campbell, Richard A.
    Inst Laue Langevin, 71 Ave Martyrs,CS20156, F-38042 Grenoble 9, France.;Univ Manchester, Div Pharm & Optometry, Manchester M13 9PT, Lancs, England..
    Johnson, C. Magnus
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Propofol adsorption at the air/water interface: a combined vibrational sum frequency spectroscopy, nuclear magnetic resonance and neutron reflectometry study2019In: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 15, no 1, p. 38-46Article in journal (Refereed)
    Abstract [en]

    Propofol is an amphiphilic small molecule that strongly influences the function of cell membranes, yet data regarding interfacial properties of propofol remain scarce. Here we consider propofol adsorption at the air/water interface as elucidated by means of vibrational sum frequency spectroscopy (VSFS), neutron reflectometry (NR), and surface tensiometry. VSFS data show that propofol adsorbed at the air/ water interface interacts with water strongly in terms of hydrogen bonding and weakly in the proximity of the hydrocarbon parts of the molecule. In the concentration range studied there is almost no change in the orientation adopted at the interface. Data from NR show that propofol forms a dense monolayer with a thickness of 8.4 angstrom and a limiting area per molecule of 40 angstrom(2), close to the value extracted from surface tensiometry. The possibility that islands or multilayers of propofol form at the air/water interface is therefore excluded as long as the solubility limit is not exceeded. Additionally, measurements of the 1H NMR chemical shifts demonstrate that propofol does not form dimers or multimers in bulk water up to the solubility limit.

  • 33.
    Norrfors, K. Karin
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Björkbacka, Åsa
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Kessler, Amanda
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Wold, Susanna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    γ-radiation induced corrosion of copper in bentonite-water systems under anaerobic conditions2018In: Radiation Physics and Chemistry, ISSN 0969-806X, E-ISSN 1879-0895, Vol. 144, p. 8-12Article in journal (Refereed)
    Abstract [en]

    In this work we have experimentally studied the impact of bentonite clay on the process of radiation-induced copper corrosion in anoxic water. The motivation for this is to further develop our understanding of radiation-driven processes occurring in deep geological repositories for spent nuclear fuel where copper canisters containing the spent nuclear fuel will be embedded in compacted bentonite. Experiments on radiation-induced corrosion in the presence and absence of bentonite were performed along with experiments elucidating the impact irradiation on the Cu2+ adsorption capacity of bentonite. The experiments presented in this work show that the presence of bentonite clay has no or very little effect on the magnitude of radiation-induced corrosion of copper in anoxic aqueous systems. The absence of a protective effect similar to that observed for radiation-induced dissolution of UO2 is attributed to differences in the corrosion mechanism. This provides further support for the previously proposed mechanism where the hydroxyl radical is the key radiolytic oxidant responsible for the corrosion of copper. The radiation effect on the bentonite sorption capacity of Cu2+ (reduced capacity) is in line with what has previously been reported for other cations. The reduced cation sorption capacity is partly attributed to a loss of Al-OH sites upon irradiation.

  • 34.
    Parrilla, Marc
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Cuartero, Maria
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Crespo, Gaston A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Wearable potentiometric ion sensors2019In: TrAC. Trends in analytical chemistry, ISSN 0165-9936, E-ISSN 1879-3142, Vol. 110, p. 303-320Article, review/survey (Refereed)
    Abstract [en]

    Wearable potentiometric ion sensors (WPISs) have become an exciting analytical platform that combines chemical, material and electronic efforts to supply physiological information during certain human activities. The real possibility of wearing an analytical device with diverse configurations-sweatband, patches, garments-without disturbing the welfare of the carrier has enabled potentiometric ion sensors both as health quality and sport performance controllers. Recent studies show a large involvement of WPISs in the following of critical biomarkers (timely or continuously), such as sodium, potassium, calcium, magnesium, ammonium and chloride, which are present at relatively high concentrations in sweat (similar to mM levels). Certainly, the non-invasive nature of WPISs and other significant features, e.g., simplicity and cost-effectiveness, have broadened new horizons in relation to applied analytical chemistry. This has been pointed out in the literature over the last decade with the predominance of two analytical outcomes: (i) the improvement of sport performance as a result of continuous detection of ions in sweat (health status of the individual) while decreasing physiological complications (injuries, muscle cramps, fatigue and dehydration) during practice; and (ii) advancements in clinical diagnostics and preventive medicine as a consequence of the monitoring of the health status of patients suffering from any kind of disorder. Beyond the undeniable importance of the integration of WPISs to satisfy current societal needs, the following crucial questions about misleading and missing analytical features need to be answered: To what extent is WPIS technology a reliable analytical tool for the quantification of ions? Is cross-validation the current bottleneck toward further progress? Which are the fundamental steps involving the ion-selective electrode side that would benefit WPIS outcomes? Why is sweat the main (and almost the only) biological fluid to be monitored by WPISs? What is the best sampling strategy to be incorporated into WPIS devices for on-body monitoring of sweat? Which precision limits should be considered to assure a reliable decision-making process? Accordingly, this review focuses on the progression of WPISs from an analytical perspective-merely our vision of the field-within the period between 2010 and 2018. An updated search using specific keywords (wearable, ion, potentiometry, sensor) provided 43 contributions, which are herein highlighted, with a sustainable acceleration over the last three years. Thus, this review describes the current state of WPIS technology, the construction of wearable all-solid-state potentiometric sensors, critical requirements of potentiometric sensors to be fulfilled in a wearable configuration and key features regarding the ideal implementation of WPISs as reliable messengers of physiological information in real scenarios.

  • 35.
    Parrilla, Marc
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Cuartero, Maria
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Sanchez, Sara Padrell
    Karolinska Inst, Dept Clin Sci Intervent & Technol, K 57, SE-14186 Stockholm, Sweden.;Karolinska Univ Sjukhuset, Div Obstet & Gynecol, S-14186 Stockholm, Sweden..
    Rajabi, Mina
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Roxhed, Niclas
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Niklaus, Frank
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Crespo, Gaston A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Wearable All-Solid-State Potentiometric Microneedle Patch for Intradermal Potassium Detection2019In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 91, no 2, p. 1578-1586Article in journal (Refereed)
    Abstract [en]

    A new analytical all-solid-state platform for intradermal potentiometric detection of potassium in interstitial fluid is presented here. Solid microneedles are modified with different coatings and polymeric membranes to prepare both the potassium-selective electrode and reference electrode needed for the potentiometric readout. These microneedle-based electrodes are fixed in an epidermal patch suitable for insertion into the skin. The analytical performances observed for the potentiometric cell (Nernstian slope, limit of detection of 10(-4.9) potassium activity, linear range of 10(-4.2) to 10(-1.1), drift of 0.35 +/- 0.28 mV h(-1)), together with a fast response time, adequate selectivity, and excellent reproducibility and repeatability, are appropriate for potassium analysis in interstitial fluid within both clinical and harmful levels. The potentiometric response is maintained after several insertions into animal skin, confirming the resiliency of the microneedle-based sensor. Ex vivo tests based on the intradermal detection of potassium in chicken and porcine skin demonstrate that the microneedle patch is suitable for monitoring potassium changes inside the skin. In addition, the dimensions of the microneedles modified with the corresponding layers necessary to enhance robustness and provide sensing capabilities (1000 mu m length, 45 degrees tip angle, 15 mu m thickness in the tip, and 435 mu m in the base) agree with the required ranges for a painless insertion into the skin. In vitro cytotoxicity experiments showed that the patch can be used for at least 24 h without any side effect for the skin cells. Overall, the developed concept constitutes important progress in the intradermal analysis of ions related to an electrolyte imbalance in humans, which is relevant for the control of certain types of diseases.

  • 36.
    Paulraj, Thomas
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Wennmalm, Stefan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Experimental Biomolecular Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab. ..
    Riazanova, Anastasia, V
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Wu, Qiong
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Crespo, Gaston A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Svagan, Anna J.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Porous Cellulose Nanofiber-Based Microcapsules for Biomolecular Sensing2018In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 48, p. 41146-41154Article in journal (Refereed)
    Abstract [en]

    Cellulose nanofibers (CNFs) have recently attracted a lot of attention in sensing because of their multifunctional character and properties such as renewability, nontoxicity, biodegradability, printability, and optical transparency in addition to unique physicochemical, barrier, and mechanical properties. However, the focus has exclusively been devoted toward developing two-dimensional sensing platforms in the form of nanopaper or nanocellulose-based hydrogels. To improve the flexibility and sensing performance in situ, for example, to detect biomarkers in vivo for early disease diagnostics, more advanced CNF-based structures are needed. Here, we developed porous and hollow, yet robust, CNF-based microcapsules using only the primary plant cell wall components, CNF, pectin, and xyloglucan, to assemble the capsule wall. The fluorescein isothiocyanate-labeled dextrans with M-w of 70 and 2000 kDa could enter the hollow capsules at a rate of 0.13 +/- 0.04 and 0.014 +/- 0.009 s(-1), respectively. This property is very attractive because it minimizes the influence of mass transport through the capsule wall on the response time. As a proof of concept, glucose oxidase (GOx) enzyme was loaded (and cross-linked) in the microcapsule interior with an encapsulation efficiency of 68 +/- 2%. The GOx-loaded microcapsules were immobilized on a variety of surfaces (here, inside a flow channel, on a carbon-coated sensor or a graphite rod) and glucose concentrations up to 10 mM could successfully be measured. The present concept offers new opportunities in the development of simple, more efficient, and disposable nanocellulose-based analytical devices for several sensing applications including environmental monitoring, healthcare, and diagnostics.

  • 37.
    Phuyal, Dibya
    et al.
    Uppsala Univ, Dept Phys & Astron, Solid State Phys, Angstrom Lab, Box 516, SE-75121 Uppsala, Sweden..
    Safdari, Majid
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Pazoki, Meysam
    Uppsala Univ, Dept Engn Sci, Solid State Phys, Angstrom Lab, SE-75121 Uppsala, Sweden..
    Liu, Peng
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Philippe, Bertrand
    Uppsala Univ, Dept Phys & Astron, Solid State Phys, Angstrom Lab, Box 516, SE-75121 Uppsala, Sweden..
    Kyashnina, Kristina O.
    ESRF, Rossendorf Beamline, CS40220, F-38043 Grenoble 9, France.;HZDR, Inst Resource Ecol, POB 510119, D-01314 Dresden, Germany..
    Karis, Olof
    Uppsala Univ, Dept Phys & Astron, Solid State Phys, Angstrom Lab, Box 516, SE-75121 Uppsala, Sweden..
    Butorin, Sergei M.
    Uppsala Univ, Dept Phys & Astron, Solid State Phys, Angstrom Lab, Box 516, SE-75121 Uppsala, Sweden..
    Rensmo, Hakan
    Uppsala Univ, Dept Phys & Astron, Solid State Phys, Angstrom Lab, Box 516, SE-75121 Uppsala, Sweden..
    Edvinsson, Tomas
    Uppsala Univ, Dept Engn Sci, Solid State Phys, Angstrom Lab, SE-75121 Uppsala, Sweden..
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Gardner, James M.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Electronic Structure of Two-Dimensional Lead(II) Iodide Perovskites: An Experimental and Theoretical Study2018In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 30, no 15, p. 4959-4967Article in journal (Refereed)
    Abstract [en]

    Layered two-dimensional (2D) hybrid organic-inorganic perovskites (HOP) are promising materials for light-harvesting applications because of their chemical stability, wide flexibility in composition and dimensionality, and increases in photovoltaic power conversion efficiencies. Three 2D lead iodide perovskites were studied through various X-ray spectroscopic techniques to derive detailed electronic structures and band energetics profiles at a titania interface. Core-level and valence band photoelectron spectra of HOP were analyzed to resolve the electronic structure changes due to the reduced dimensionality of inorganic layers. The results show orbital narrowing when comparing the HOP, the layered precursor PbI2, and the conventional 3D (CH3NH3)PbI3 such that different localizations of band edge states and narrow band states are unambiguously due to the decrease in dimensionality of the layered HOPs. Support from density functional theory calculations provide further details on the interaction and band gap variations of the electronic structure. We observed an interlayer distance dependent dispersion in the near band edge electronic states. The results show how tuning the interlayer distance between the inorganic layers affects the electronic properties and provides important design principles for control of the interlayer charge transport properties, such as the change in effective charge masses as a function of the organic cation length. The results of these findings can be used to tune layered materials for optimal functionality and new applications.

  • 38.
    Pourmand, Payam
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Chemistry.
    Hedenqvist, Mikael S.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Furo, Istvan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Chemistry.
    Gedde, Ulf W
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Deterioration of highly filled EPDM rubber by thermal ageing in air: Kinetics and non-destructive monitoring2017In: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 64, p. 267-276Article in journal (Refereed)
    Abstract [en]

    The effects of air ageing at different temperatures between 110 and 170 degrees C on cable transit seals based on highly filled EPDM rubber used in nuclear power plants were studied. The changes of the macroscopic mechanical properties (Young's modulus, indentation modulus and strain-at-break) were in accordance with the Arrhenius equation with an activation energy of 110 kJ mol(-1). Profiling to assess the structure and property gradients within aged blocks was performed via IR spectroscopy, micro-indentation, gravimetric analysis of n-heptane-extracted samples and non-invasive portable NMR spectroscopy. A previously developed methodology was used to separate the deterioration into three different processes: polymer oxidation that was diffusion-limited at all temperatures, migration of low-molar-mass species to the surrounding media and anaerobic changes to the polymer network. The methodology allowed the assessment of the kinetics (rate as a function of time and temperature) of the different processes. It was noticed that polymer oxidation yielded more crosslinking at higher temperatures than at lower temperatures. The data obtained by both the portable NMR (a non-invasive method) and the indentation modulus profiling showed correlations with strain-at-break data, indicating their usefulness as condition monitoring methods.

  • 39.
    Rohlmann, Patrick
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.). KTH Royal Inst Technol, Machine Design, Stockholm, Sweden..
    Munavirov, Bulat
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Furo, Istvan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Antzutkin, Oleg
    Lulea Univ Technol, Chem Interfaces, Lulea, Sweden..
    Rutland, Mark W.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. RISE Res Inst Sweden, Surfaces Proc & Formulat, Stockholm, Sweden.
    Glavatskih, Sergei
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.). Univ Ghent, Dept Elect Energy Met Mech Construct & Syst, Ghent, Belgium.
    Non-halogenated Ionic Liquid Dramatically Enhances Tribological Performance of Biodegradable Oils2019In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 7, article id 98Article in journal (Refereed)
    Abstract [en]

    It is demonstrated that a phosphonium orthoborate ionic liquid may serve as a wear reducing additive in biodegradable oils at steel-steel surfaces in the boundary lubrication regime. Tribological tests were performed in a bail-on-three plate configuration. A set of surface characterization techniques-SEM/EDS, FIB and white light interferometry were used to characterize surfaces following the tribotests and to observe the formation of any tribofilms. B-11 NMR was used to follow changes in the composition of the ionic-liquid-oil blends and to identify boron-containing decomposition products after the tribotests. The ionic liquid reduces the wear of steel surfaces by up to 92% compared to the neat oil at 90 degrees C; it is shown that the reduction in wear can be correlated with the formation of boron enriched patches in the boundary films.

  • 40.
    Rokhas, Maria Khihon
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Ronn, Johanna Liljestrand
    Uppsala Univ, Dept Ecol & Genet Anim Ecol, Uppsala, Sweden..
    Wiklund, Christer
    Stockholm Univ, Dept Zool, Ecol, Stockholm, Sweden..
    Emmer, Åsa
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Analysis of butterfly reproductive proteins using capillary electrophoresis and mass spectrometry2019In: Analytical Biochemistry, ISSN 0003-2697, E-ISSN 1096-0309, Vol. 566, p. 23-26Article in journal (Refereed)
    Abstract [en]

    A method for analysis of proteins from spermatophores transferred from male to female Pieris napi butterflies during mating has been developed. The proteins were solubilized from the dissected spermatophores using different solubilization agents (water, methanol, acetonitrile and hexafluoroisopropanol). Capillary electrophoresis (CE) analysis was performed using an acidic background electrolyte containing a fluorosurfactant to avoid protein-wall adsorption, and to increase separation performance. The samples were also analyzed with matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS), in a lower m/z range (1000-6000) and a higher m/z range (6000-12000). Solubilization with different solvents and the use of alternative matrices gave partly complementary profiles.

  • 41.
    Romson, Joakim
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Emmer, Åsa
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    ESI-MSn Analysis of Recombinant Human OsteopontinManuscript (preprint) (Other academic)
    Abstract [en]

    The low-abundance protein osteopontin is implicated in several serious diseases, where its concentration andglycosylation patterns might be analyzed for its use as a biomarker. The glycosylation has previously been studied andcharacterized mainly on digested protein. Allowing analysis of glycosylation using the intact protein would reduce theworkload and analysis time, as well as introducing less potential sources of error and bias. Here, the detection of intactosteopontin by ESI-MS is presented. By using a matrix with a high proportion of isopropanol, osteopontin could be detectedand fragmented in tandem MS at 10 µg/mL by direct infusion. A lower osteopontin mass was also present in the sample. Theresults open the possibilities of further analysis of osteopontin by tandem MS and suggests a reporter ion.

  • 42.
    Romson, Joakim
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Jacksen, Johan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. Biotage Sweden AB, Uppsala, Sweden..
    Emmer, Åsa
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    An automated system for CE-MALDI and on-target digestion under a fluorocarbon lid applied on spermatophore proteins from Pieris napi2019In: Journal of chromatography. B, ISSN 1570-0232, E-ISSN 1873-376X, Vol. 1104, p. 228-233Article in journal (Refereed)
    Abstract [en]

    A method for off-line CE-MALDI-TOF-MS and MS2, and on-target digestion under a fluorocarbon lid was developed and applied for the analysis of proteins in the spermatophore of the butterfly Pieris napi. Fractionation revealed many peptides otherwise not detected or resolved. Automated fractionation was performed with an in-lab developed robotic system, and automated on-target tryptic digestion under a fluorocarbon lid was demonstrated with the same system. Fractionation onto a pre-structured MALDI-concentration plate facilitated aligned deposition of trypsin and MALDI-matrix with the deposited sample, also under the fluorocarbon lid. Some indications of indigenous proteolysis of spermatophore proteins were seen, and searching MS2 spectra suggested three tentative sequence homologies to P. rapae. The study demonstrates the functionality of the lab-made robot. Detailed manufacturing instructions and code are provided. The feasibility of automated on-target digestion under a fluorocarbon lid, and the usefulness of a structured concentration plate in CE-MALDI fractionation was shown. Further, it constitutes a preliminary study of P. napi spermatophore proteins.

  • 43.
    Romson, Joakim
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Jacksén, Johan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Emmer, Åsa
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    An automated system for CE-MALDI and on-target digestion under a fluorocarbon lid applied on spermatophore proteins from Pieris napiIn: Journal of chromatography. B, ISSN 1570-0232, E-ISSN 1873-376XArticle in journal (Refereed)
    Abstract [en]

    A method for off-line CE‑MALDI‑TOF-MS and MS2, and on-target digestion under a fluorocarbon lid was developed and applied for the analysis of proteins in the spermatophore of the butterfly Pieris napi. Fractionation revealed many peptides otherwise not detected or resolved. Automated fractionation was performed with an in-lab developed robotic system, and automated on-target tryptic digestion under a fluorocarbon lid was demonstrated with the same system. Fractionation onto a pre-structured MALDI-concentration plate facilitated aligned deposition of trypsin and MALDI-matrix with the deposited sample, also under the fluorocarbon lid. Some indications of indigenous proteolysis of spermatophore proteins were seen, and searching MS2 spectra suggested three tentative sequence homologies to P. rapae. The study demonstrates the functionality of the lab-made robot. Detailed manufacturing instructions and code are provided. The feasibility of automated on-target digestion under a fluorocarbon lid, and the usefulness of a structured concentration plate in CE-MALDI fractionation was shown. Further, it constitutes a preliminary study of P. napi spermatophore proteins.

  • 44.
    Romson, Joakim
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Methods for protein analysis by capillary electrophoresis and mass spectrometry2018Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Protein analysis is important to understanding biological systems, but sample diversity necessitates a multitude of analysis techniques and methods. Challenges that are addressed include analysis of low abundance samples, fractionation to reduce sample complexity, and automation to reduce time and cost.

    Matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) is an important technique for protein characterization. In Paper I, the sensitivity of MALDI-MS was enhanced through the fabrication of a hydrophobic coating for the MALDI target plate, yielding analyte concentration. The plate outperformed a commercial concentration plate.

    Capillary electrophoresis (CE) separation offers low sample consumption and high efficiency, and in Paper II, offline CE-MALDI-MS fractionation was employed. A robot system for automation was constructed and used in analysis of spermatophore proteins from the butterfly Pieris napi. The robot was also used in automated on-target trypsin digestion under a lid of liquid fluorocarbons, a simpler and cheaper alternative to controlled humidity chambers. An indication of indigenous proteolysis of the sample was seen.

    Electrospray ionization (ESI) is the other technique for protein analysis in MS. In Paper III, the biomarker protein osteopontin (OPN) was analyzed by ESI-MS in order to find suitable conditions for its detection. A preliminary optimization of solvents and ionization conditions was done, and tandem MS (MSn) performed to increase the reliability of identification.

    The full text will be freely available from 2019-12-19 11:25
  • 45.
    Saki, Zahra
    et al.
    Sharif Univ Technol, Phys Dept, Tehran 14588, Iran.;Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, Box 523, S-75120 Uppsala, Sweden..
    Aitola, Kerttu
    Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, Box 523, S-75120 Uppsala, Sweden.;Aalto Univ Sch Sci, New Energy Technol Grp, Dept Appl Phys, POB 15100, Aalto 00076, Finland..
    Sveinbjornsson, Kari
    Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, Box 523, S-75120 Uppsala, Sweden..
    Yang, Wenxing
    Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, Box 523, S-75120 Uppsala, Sweden..
    Svanstrom, Sebastian
    Uppsala Univ, Dept Phys & Astron Mol & Condensed Matter Phys, Box 516, S-75120 Uppsala, Sweden..
    Cappel, Ute B.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. Uppsala Univ, Dept Phys & Astron Mol & Condensed Matter Phys, Box 516, S-75120 Uppsala, Sweden.;.
    Rensmo, Hakan
    Uppsala Univ, Dept Phys & Astron Mol & Condensed Matter Phys, Box 516, S-75120 Uppsala, Sweden..
    Johansson, Erik M. J.
    Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, Box 523, S-75120 Uppsala, Sweden..
    Taghavinia, Nima
    Sharif Univ Technol, Phys Dept, Tehran 14588, Iran.;Sharif Univ Technol, Inst Nanosci & Nanotechnol, Tehran 14588, Iran..
    Boschloo, Gerrit
    Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, Box 523, S-75120 Uppsala, Sweden..
    The synergistic effect of dimethyl sulfoxide vapor treatment and C-60 electron transporting layer towards enhancing current collection in mixed-ion inverted perovskite solar cells2018In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 405, p. 70-79Article in journal (Refereed)
    Abstract [en]

    Inverted perovskite solar cells (PSCs) have been introduced as better candidate for roll-to-roll printing and scaleup than their conventional configuration counterparts, while their fabrication is technically more demanding. The common light absorbing layer in inverted PSCs is the single cation methylammonium lead iodide (MAPbI(3)) perovskite, whereas mixed-ion perovskites are chemically more stable. In mixed-ion perovskites, where FA (formamidinium) is the main replacement for MA, the electron affinity is larger than in MAPbI3 perovskites, leading to possible barriers against photoelectron collection by the electron transporting layer (ETL). In this paper we report on a mixed-ion (FAPbI(3))(0.83)(MAPbBr(3))(0.17) inverted PSC with improved photocurrent through using a dimethyl sulfoxide vapor treatment of perovskite layer and replacing the conventional [6,6]-phenyl-C-71 butyric acid methyl ester (PC70BM) with C-60/bathocuproine (BCP) as more effective ETL. The treatment of perovskite layer results in reduction of impurity phases of 8-FAPbI(3) and Pbl(2). Photoluminescence and open circuit voltage decay data demonstrate better charge carrier collection by the C-60/BCP compared to the PC70BM ETL, and an electron barrier for the back flow of electrons from ETL to perovskite. Our improvements in perovskite crystalization and electron transfer layer simultaneously lead to increasing the current density from 10 to 21 mA cm(-2).

  • 46.
    Schaefer, A.
    et al.
    Lund Univ, Dept Synchrotron Radiat Res, POB 118, SE-22100 Lund, Sweden.;Chalmers Univ Technol, Competence Ctr Catalysis, S-41296 Gothenburg, Sweden..
    Lanzilotto, V.
    Uppsala Univ, Dept Phys & Astron, POB 516, SE-75120 Uppsala, Sweden..
    Cappel, Ute B.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. Uppsala Univ, Dept Phys & Astron, POB 516, SE-75120 Uppsala, Sweden.
    Uvdal, P.
    Lund Univ, Dept Chem, Chem Phys, POB 124, SE-22100 Lund, Sweden..
    Borg, A.
    NTNU Norwegian Univ Sci & Technol, Dept Phys, NO-07491 Trondheim, Norway..
    Sandell, A.
    Uppsala Univ, Dept Phys & Astron, POB 516, SE-75120 Uppsala, Sweden..
    First layer water phases on anatase TiO2(101)2018In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 674, p. 25-31Article in journal (Refereed)
    Abstract [en]

    The anatase TiO2(101) surface and its interaction with water is an important topic in oxide surface chemistry. Firstly, it benchmarks the properties of the majority facet of TiO2 nanoparticles and, secondly, there is a controversy as to whether the water molecule adsorbs intact or deprotonates. We have addressed the adsorption of water on anatase TiO2(101) by synchrotron radiation photoelectron spectroscopy. Three two-dimensional water structures are found during growth at different temperatures: at 100 K, a metastable structure forms with no hydrogen bonding between the water molecules. In accord with prior literature, we assign this phase to chains of disordered molecules. Growth 160 K results in a metastable structure with expressed hydrogen bonding between the water molecules. At 190 K, the water molecules become disordered as the thermal energy is too high and hence the hydrogen bonds break. The result is a structure with isolated monomers. Partial dissociation is observed for all three growths, with the molecular state only slightly favored in energy (20-40 meV) over the dissociated state. Heating of a thick film leads to more dissociation compared to a bilayer, when formed at 100 K. Thus, extending the water network facilitates proton transport and hence dissociation. The results reconcile apparent conflicting experimental results previously obtained by scanning tunneling microscopy (STM) and core level photoelectron spectroscopy.

  • 47.
    Schaefer, A.
    et al.
    Chalmers Univ Technol, Dept Chem & Chem Engn, S-41296 Gothenburg, Sweden.;Chalmers Univ Technol, Competence Ctr Catalysis, S-41296 Gothenburg, Sweden..
    Lanzilotto, V.
    Uppsala Univ, Dept Phys & Astron, POB 516, SE-75120 Uppsala, Sweden..
    Cappel, Ute
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. Uppsala Univ, Dept Phys & Astron, POB 516, SE-75120 Uppsala, Sweden.
    Uvdal, P.
    Lund Univ, Dept Chem, Chem Phys, POB 124, SE-22100 Lund, Sweden..
    Borg, A.
    NTNU Norwegian Univ Sci & Technol, Dept Phys, NO-7491 Trondheim, Norway..
    Sandell, A.
    Uppsala Univ, Dept Phys & Astron, POB 516, SE-75120 Uppsala, Sweden..
    Defect-Induced Water Bilayer Growth on Anatase TiO2(101)2018In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 34, no 37, p. 10856-10864Article in journal (Refereed)
    Abstract [en]

    Preparing an anatase TiO2(101) surface with a high density of oxygen vacancies and associated reduced Ti species in the near-surface region results in drastic changes in the water adsorption chemistry compared to adsorption on a highly stoichiometric surface. Using synchrotron radiation excited photoelectron spectroscopy, we observe a change in the water growth mode, from layer-by-layer growth on the highly stoichiometric surface to bilayer growth on the reduced surface. Furthermore, we have been able to observe enrichment at the surface upon water adsorption. The Ti3+ enrichment occurs concomitant with effective water dissociation into hydroxyls with a very high thermal stability. The water bilayer on the reduced surface is thermally more stable than that on the stoichiometric surface, and it is more efficient in promoting further water dissociation upon heating. The results thus show how the presence of subsurface defects can alter the wetting mechanism of an oxide surface.

  • 48.
    Sophonrat, Nanta
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Sandström, Linda
    RISE ETC.
    Svanberg, Rikard
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Han, Tong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Dvinskikh, Sergey
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Lousada, Claudio M.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Yang, Weihong
    KTH, Superseded Departments (pre-2005), Materials Science and Engineering.
    Ex-situ catalytic pyrolysis of a mixture of PVC and cellulose using calcium oxide for HCl adsorption and catalytic reforming of the pyrolysis productsManuscript (preprint) (Other academic)
    Abstract [en]

    In the context of chemical recycling of mixed plastics and paper, multi-temperature step pyrolysis has shown good potential for the separation of oxygenated products from hydrocarbons. Here, we report results of an investigation of the first pyrolysis step at low temperature, which involves the dehydrochlorination of polyvinyl chloride (PVC) and the pyrolysis of cellulose—the main component of paper. Calcium oxide (CaO), selected for its chloride adsorption ability and its catalytic activity on biooil deoxygenation, was used for upgrading the downstream products from the pyrolysis. Additionally, we studied the performance of CaO for the simultaneous adsorption of HCl and for reforming cellulose pyrolysates in the temperature range of 300-600 °C with feedstock to CaO ratios of 1:0.2, 1:0.4 and 1:1. It was found that the suitable catalytic temperature for HCl and acetic acid adsorption is lower than 400 °C. This is due to the reaction of CaO with water that causes the desorption of HCl at temperatures above 400 °C. A larger amount of CaO resulted in a more efficient reduction of acids and the organic liquids were found to have lower amounts of oxygen. A comparison between the cases of neat and mixed feedstock showed that pyrolysis of mixed feedstock produced more water, H2, CO and polycyclic aromatic hydrocarbons (PAHs) when compared to the case of neat materials over CaO.

  • 49.
    Starkholm, Allan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Kloo, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Svensson, Per H.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Polyiodide Hybrid Perovskites: A Strategy To Convert Intrinsic 2D Systems into 3D Photovoltaic Materials2019In: ACS Applied Energy Materials, ISSN 2574-0962, Vol. 2, no 1, p. 477-485Article in journal (Refereed)
    Abstract [en]

    Two new organic inorganic hybrid perovskite compounds, (Me3S)(2)Pb5I14*2I(2) (1) and (C8H11S)(2)Pb2I6*I-2 (2), have been synthesized and subsequently characterized in this study. The materials were synthesized from facile one-pot, one-step reactions of lead iodide, corresponding sulfide, methanol, iodine, and hydroiodic acid in the case of 2. Structural analysis reveals the presence of polyiodide entities in both compounds. Compound 1 contains triiodide anions, I-3(-), that are uniquely shared between the 2D inorganic slabs, forming a 3D network. Both 1 and 2 have I-2 molecules that are bridging the inorganic slabs through a structural motif that can be regarded as a tetraiodide anion, I-4(2-). Optical spectroscopy shows band gaps of 1.86 eV for 1 and 1.89 eV for 2. The optoelectronic properties were further investigated with band structure calculations. Single-crystal IV-characteristics of 1 show that the compound is photoactive confirming it as a promising photovoltaic candidate. Compound 1 highlights a novel strategy of designing 3D semiconducting hybrid materials by incorporating polyiodides to provide direct geometric and electronic connections between the semiconducting inorganic perovskite sheets.

  • 50.
    Svanström, Sebastian
    et al.
    Uppsala Univ, Dept Phys & Astron, Div Mol & Condensed Matter Phys, Box 516, SE-75120 Uppsala, Sweden..
    Jacobsson, T. Jesper
    Uppsala Univ, Dept Chem, Angstrom Lab, Box 538, S-75121 Uppsala, Sweden..
    Sloboda, Tamara
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    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..
    Rensmo, Hakan
    Uppsala Univ, Dept Phys & Astron, Div Mol & Condensed Matter Phys, Box 516, SE-75120 Uppsala, Sweden..
    Cappel, Ute B.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Effect of halide ratio and Cs+ addition on the photochemical stability of lead halide perovskites2018In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 6, no 44, p. 22134-22144Article in journal (Refereed)
    Abstract [en]

    Lead halide perovskite solar cells with multi-cation/mixed halide materials now give power conversion efficiencies of more than 20%. The stability of these mixed materials has been significantly improved through the addition of Cs+ compared to the original methylammonium lead iodide. However, it remains one of the most significant challenges for commercialisation. In this study, we use photoelectron spectroscopy (PES) in combination with visible laser illumination to study the photo-stability of perovskite films with different compositions. These include Br : I ratios of 50 : 50 and 17 : 83 and compositions with and without Cs+. For the samples without Cs and the 50 : 50 samples, we found that the surface was enriched in Br and depleted in I during illumination and that some of the perovskite decomposed into Pb-0, organic halide salts, and iodine. After illumination, both of these reactions were partially reversible. Furthermore, the surfaces of the films were enriched in organic halide salts indicating that the cations were not degraded into volatile products. With the addition of Cs+ to the samples, photo-induced changes were significantly suppressed for a 50 : 50 bromide to iodide ratio and completely suppressed for perovskites with a 17 : 83 ratio at light intensities exceeding 1 sun equivalent.

12 1 - 50 of 58
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