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  • 1.
    Abdelhamid, Hani Nasser
    et al.
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden.;Assiut Univ, Dept Chem, Adv Multifunct Mat Lab, Assiut 71515, Egypt..
    El-Zohry, Ahmed M.
    Uppsala Univ, Dept Chem, Angstrom Labs, POB 523, S-75120 Uppsala, Sweden..
    Cong, Jiayan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Thersleff, Thomas
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden..
    Karlsson, Karl Martin
    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.
    Zou, Xiaodong
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden..
    Towards implementing hierarchical porous zeolitic imidazolate frameworks in dye-sensitized solar cells2019In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 6, no 7, article id 190723Article in journal (Refereed)
    Abstract [en]

    A one-pot method for encapsulation of dye, which can be applied for dye-sensitized solar cells (DSSCs), and synthesis of hierarchical porous zeolitic imidazolate frameworks (ZIF-8), is reported. The size of the encapsulated dye tunes the mesoporosity and surface area of ZIF-8. The mesopore size, Langmuir surface area and pore volume are 15 nm, 960-1500 m(2). g(-1) and 0.36-0.61 cm(3). g(-1), respectively. After encapsulation into ZIF-8, the dyes show longer emission lifetimes (greater than 4-8-fold) as compared to the corresponding non-encapsulated dyes, due to suppression of aggregation, and torsional motions.

  • 2.
    Abreu, Barbara
    et al.
    Univ Porto, Fac Sci, Dept Chem & Biochem, CIQUP, Rua Campo Alegre, P-4169007 Porto, Portugal..
    Rocha, Jessica
    Univ Porto, Fac Sci, Dept Chem & Biochem, CIQUP, Rua Campo Alegre, P-4169007 Porto, Portugal..
    Ferreira Fernandes, Ricardo Manuel
    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..
    Furo, Istvan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Marques, Eduardo F.
    Univ Porto, Fac Sci, Dept Chem & Biochem, CIQUP, Rua Campo Alegre, P-4169007 Porto, Portugal..
    Gemini surfactants as efficient dispersants of multiwalled carbon nanotubes: Interplay of molecular parameters on nanotube dispersibility and debundling2019In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 547, p. 69-77Article in journal (Refereed)
    Abstract [en]

    Surfactants have been widely employed to debundle, disperse and stabilize carbon nanotubes in aqueous solvents. Yet, a thorough understanding of the dispersing mechanisms at molecular level is still warranted. Herein, we investigated the influence of the molecular structure of gemini surfactants on the dispersibility of multiwalled carbon nanotubes (MWNTs). We used dicationic n-s-n gemini surfactants, varying n and s, the number of alkyl tail and alkyl spacer carbons, respectively; for comparisons, single-tailed surfactant homologues were also studied. Detailed curves of dispersed MWNT concentration vs. surfactant concentration were obtained through a stringently controlled experimental procedure, allowing for molecular insight. The gemini are found to be much more efficient dispersants than their single-tailed homologues, i.e. lower surfactant concentration is needed to attain the maximum dispersed MWNT concentration. In general, the spacer length has a comparatively higher influence on the dispersing efficiency than the tail length. Further, scanning electron microscopy imaging shows a sizeable degree of MWNT debundling by the gemini surfactants in the obtained dispersions. Our observations also point to an adsorption process that does not entail the formation of micelle-like aggregates on the nanotube surface, but rather coverage by individual molecules, among which the ones that seem to be able to adapt best to the nanotube surface provide the highest efficiency. These studies are relevant for the rational design and choice of optimal dispersants for carbon nanomaterials and other similarly water-insoluble materials.

  • 3.
    Ali, Aya
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Reaction of Copper and Copper(I) Iodide with Iodine and Strong Field Ligands2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Perovskit solceller (PSCs) är kända som 'ljusomvandling' enheter med ökad omvandlingseffektivitiet (PCE). PSCs är kända för detta flexibilitet och hög tolerans mot defekter och består av fem lager med olika material och egenskaper. De fem lagren är följande; transparant elektrod, elektron ledande lager (ETL), perovskit lager, hål ledande lager (HTL) och metallelektroden. 

    Detta forskningsarbete fokuserar på metallelektroden (Cu-tunn film), HTL (CuI-tunn film) och det aktiva lagret (CuI-komplex). 

    Syftet med denna studie är att undersöka effekten av olika tjocklekar på ytans morfologi och grovhet för att se mängden jod som tränger sig genom filmen genom att beräkna volymen. 

    Resultatet av denna studie visar att ökad tjocklek leder till ökad grovhet. Man ser även att en ökad tjocklek leder till ett mer homogent och jämn yta, och dessutom ökar kornstorleken, vilket tyder på att kvaliten av kristallisationen förbättras. 

    Slutligen, genom att känna till tjockleken och storleken (arean) på ytan av proverna kunde man beräkna volymen för att indikera mängden jod som trängt sig genom filmen. Resultatet av denna del indikerade att ju tjockare provet är, desto mer kommer jod att tränga sig genom filmen.

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  • 4. Andaji-Garmaroudi, Z.
    et al.
    Abdi-Jalebi, M.
    Kosasih, F. U.
    Doherty, T.
    Macpherson, S.
    Bowman, A. R.
    Man, G. J.
    Cappel, Ute B.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Rensmo, H.
    Ducati, C.
    Friend, R. H.
    Stranks, S. D.
    Elucidating and Mitigating Degradation Processes in Perovskite Light-Emitting Diodes2020In: Advanced Energy Materials, ISSN 1614-6832, E-ISSN 1614-6840, Vol. 10, no 48, article id 2002676Article in journal (Refereed)
    Abstract [en]

    Halide perovskites have attracted substantial interest for their potential as disruptive display and lighting technologies. However, perovskite light-emitting diodes (PeLEDs) are still hindered by poor operational stability. A fundamental understanding of the degradation processes is lacking but will be key to mitigating these pathways. Here, a combination of in operando and ex situ measurements to monitor the performance degradation of (Cs0.06FA0.79MA0.15)Pb(I0.85Br0.15)3 PeLEDs over time is used. Through device, nanoscale cross-sectional chemical mapping, and optical spectroscopy measurements, it is revealed that the degraded performance arises from an irreversible accumulation of bromide content at one interface, which leads to barriers to injection of charge carriers and thus increased nonradiative recombination. This ionic segregation is impeded by passivating the perovskite films with potassium halides, which immobilizes the excess halide species. The passivated PeLEDs show enhanced external quantum efficiency (EQE) from 0.5% to 4.5% and, importantly, show significantly enhanced stability, with minimal performance roll-off even at high current densities (>200 mA cm−2). The decay half-life for the devices under continuous operation at peak EQE increases from <1 to ≈15 h through passivation, and ≈200 h under pulsed operation. The results provide generalized insight into degradation pathways in PeLEDs and highlight routes to overcome these challenges.

  • 5.
    Aref, Mohaddeseh
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Ranjbari, Elias
    Univ Gothenburg, Dept Chem & Mol Biol, S-41296 Gothenburg, Sweden..
    Garcia-Guzman, Juan Jose
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Gene Technology.
    Hu, Keke
    Univ Gothenburg, Dept Chem & Mol Biol, S-41296 Gothenburg, Sweden..
    Lork, Alicia
    Univ Gothenburg, Dept Chem & Mol Biol, S-41296 Gothenburg, Sweden..
    Crespo, Gaston A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Ewing, Andrew G.
    Univ Gothenburg, Dept Chem & Mol Biol, S-41296 Gothenburg, Sweden..
    Cuartero, Maria
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Potentiometric pH Nanosensor for Intracellular Measurements: Real-Time and Continuous Assessment of Local Gradients2021In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 93, no 47, p. 15744-15751Article in journal (Refereed)
    Abstract [en]

    We present a pH nanosensor conceived for single intracellular measurements. The sensing architecture consisted of a two-electrode system evaluated in the potentiometric mode. We used solid-contact carbon nanopipette electrodes tailored to produce both the indicator (pH nanosensor) and reference electrodes. The indicator electrode was a membrane-based ion-selective electrode containing a receptor for hydrogen ions that provided a favorable selectivity for intracellular measurements. The analytical features of the pH nanosensor revealed a Nernstian response (slope of -59.5 mV/pH unit) with appropriate repeatability and reproducibility (variation coefficients of <2% for the calibration parameters), a fast response time (<5 s), adequate medium-term drift (0.7 mV h(-)(1)), and a linear range of response including physiological and abnormal cell pH levels (6.0-8.5). In addition, the position and configuration of the reference electrode were investigated in cell-based experiments to provide unbiased pH measurements, in which both the indicator and reference electrodes were located inside the same cell, each of them inside two neighboring cells, or the indicator electrode inside the cell and the reference electrode outside of (but nearby) the studied cell. Finally, the pH nanosensor was applied to two cases: (i) the tracing of the pH gradient from extra-to intracellular media over insertion into a single PC12 cell and (ii) the monitoring of variations in intracellular pH in response to exogenous administration of pharmaceuticals. It is anticipated that the developed pH nanosensor, which is a label-free analytical tool, has high potential to aid in the investigation of pathological states that manifest in cell pH misregulation, with no restriction in the type of targeted cells.

  • 6. 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-). 

  • 7.
    Aryal, Um Kanta
    et al.
    Mads Clausen Institute, Center for Advanced Photovoltaics and Thin Film Energy Devices (SDU CAPE), University of Southern Denmark, Sønderborg 6400, Denmark; SDU Climate Cluster, University of Southern Denmark, Odense 5230, Denmark.
    Pazniak, Hanna
    Université Grenoble Alpes, CNRS, Grenoble INP, LMGP, Grenoble, CS 50257, Grenoble Cedex 1 38016, France.
    Kumari, Tanya
    Mads Clausen Institute, Center for Advanced Photovoltaics and Thin Film Energy Devices (SDU CAPE), University of Southern Denmark, Sønderborg 6400, Denmark; SDU Climate Cluster, University of Southern Denmark, Odense 5230, Denmark.
    Weber, Matthieu
    Université Grenoble Alpes, CNRS, Grenoble INP, LMGP, Grenoble, CS 50257, Grenoble Cedex 1 38016, France.
    Johansson, Fredrik
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. Institut des Nanosciences de Paris, Sorbonne Universite, UMR CNRS 7588, F-75005 Paris, France.
    Vannucchi, Noemi
    Institut des Nanosciences de Paris, Sorbonne Universite, UMR CNRS 7588, F-75005 Paris, France; Division of X-ray Photon Science, Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden.
    Witkowski, Nadine
    Institut des Nanosciences de Paris, Sorbonne Universite, UMR CNRS 7588, F-75005 Paris, France.
    Turkovic, Vida
    Mads Clausen Institute, Center for Advanced Photovoltaics and Thin Film Energy Devices (SDU CAPE), University of Southern Denmark, Sønderborg 6400, Denmark; SDU Climate Cluster, University of Southern Denmark, Odense 5230, Denmark.
    Di Carlo, Aldo
    Istituto di Struttura della Materia, CNR-ISM, Via del Fosso del Cavaliere 100, Rome 00133, Italy, Via del Fosso del Cavaliere 100; CHOSE (Centre for Hybrid and Organic Solar Energy), Department of Electronic Engineering, University of Rome “Tor Vergata”, via del Politecnico 1, Rome 00133, Italy, via del Politecnico 1.
    Madsen, Morten
    Mads Clausen Institute, Center for Advanced Photovoltaics and Thin Film Energy Devices (SDU CAPE), University of Southern Denmark, Sønderborg 6400, Denmark; SDU Climate Cluster, University of Southern Denmark, Odense 5230, Denmark.
    2D MXene-Based Electron Transport Layers for Nonhalogenated Solvent-Processed Stable Organic Solar Cells2023In: ACS Applied Energy Materials, E-ISSN 2574-0962, Vol. 6, no 9, p. 4549-4558Article in journal (Refereed)
    Abstract [en]

    Implementation of 2D materials is one of the promising routes for improving the efficiency and stability of organic solar cells (OSCs). Due to their tunable optical and electronic properties, MXenes, a family of 2D transition metal carbides and nitrides, have attracted considerable attention and demonstrated their potential for next-generation solar cells. In this work, Ti3C2Tx MXene was added into ZnO precursors and applied as a modified composite electron transport layer (ETL) in PM6:N3-based inverted OSCs. The nonhalogenated solvent o-xylene was employed as the active layer solvent for the development of stable, efficient, and eco-friendly OSCs. By optimizing the concentration of Ti3C2Tx in the ZnO ETL, the solar cells exhibited power conversion efficiencies (PCEs) of 14.1 and 13.7% for 0.5 and 2 wt % MXene, respectively, as compared to neat ZnO layer devices with a PCE of 14.9%. Interestingly, the MXene-based PM6:N3 OSC devices showed superior device stability compared to the reference cells. It is demonstrated that the MXene introduced in the composite ZnO-based ETL mitigates the photocatalytic decomposition of the organic active layer on the ZnO surface, as analyzed via optical spectroscopy and hard X-ray photoelectron spectroscopy, which appears as a main reason for improved device stability. We thus report on the usage of MXene in green solvent-processed OSCs to enhance the lifetime of solar cells and thus address an important bottleneck in high-performance nonfullerene acceptor solar cells.

  • 8.
    Atapour, Masoud
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Wei, Zheng
    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.
    Lendel, Christofer
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Odnevall Wallinder, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Hedberg, Yolanda
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Metal release from stainless steel 316L in whey protein - And simulated milk solutions under static and stirring conditions2019In: Food Control, ISSN 0956-7135, E-ISSN 1873-7129, Vol. 101, p. 163-172Article in journal (Refereed)
    Abstract [en]

    Stainless steel is an important transport and processing contact material for bovine milk and dairy products. Release (migration) of metals, ions, complexes or wear debris/particles, and metal-induced protein aggregation in such environments are hence important to consider both from a corrosion and food safety perspective. This study aims on investigating the release of iron (Fe), chromium (Cr), and nickel (Ni) from AISI 316L stainless steel in contact with whey protein solutions relevant for protein drinks, and on how the whey proteins are influenced by stirring with a magnetic stir bar and metal release. Mechanistic insight is gained by parallel investigations of metal release from two reference non-protein containing solutions, a metal-complexing (citrate-containing) simulated milk solution (SMS) and a low complexing phosphate buffered saline solution (PBS). All immersion exposures were conducted at pH 6.8 for 0.5, 4, 24 and 48 hat room temperature at static and stirring conditions. All solutions and samples were investigated using different chemical, spectroscopic, microscopic, and electrochemical methods. Significantly higher amounts of Fe, Cr, and Ni were released into the whey protein solution (80 g/L) as compared to SMS and PBS. Strong enrichment of Cr in the surface oxide and reduction of the surface oxide thickness were associated with a higher amount of Ni release in the metal-complexing solutions (SMS and whey protein) compared with PBS. Stirring conditions resulted in higher amounts of metal release, enrichment of Cr in the surface oxide, and clear signs of wear of the 316L surface in all solutions compared to static conditions. The wear mechanism in the whey protein solution was different as compared to corresponding processes in SMS and PBS, involving an etching-like process and larger-sized wear debris. Electrochemical measurements at static conditions confirmed observed differences between the solutions, with the lowest corrosion resistance observed for coupons exposed in the whey protein solution, followed by SMS and PBS. Released metals in solution from the 316L coupons in contact with the whey protein solution resulted in enhanced rates of protein aggregation and precipitation of protein aggregates from solution. Further studies should be made to investigate other relevant test conditions and assess toxicological risks.

  • 9. Athanasaki, G.
    et al.
    Wang, Q
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. Arizona State Univ.
    Shi, X.
    Chauhan, N.
    Vimala, V.
    Cindrella, L.
    Ahmad, R.
    Kannan, A. M.
    Design and development of gas diffusion layers with pore forming agent for proton exchange membrane fuel cells at various relative humidity conditions2021In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 46, no 9, p. 6835-6844Article in journal (Refereed)
    Abstract [en]

    Membrane electrode assemblies are developed by incorporating gas diffusion layers (GDL) to improve the lower and higher relative humidity performance of proton exchange membrane fuel cells (PEMFCs). In the present study, gas diffusion layer samples containing microporous layers, are fabricated using carbon paper substrate, PUREBLACK® carbon powder and polyethylene glycol as pore forming agent. The GDLs are studied in single cell fuel cell, to evaluate the effect of porosity of the micro-porous layer on the performance at different operating relative humidity conditions and compared with commercial GDLs. Scanning electron microscopy and contact angle measurements indicate crack-free surface morphology and hydrophobic characteristics of the PUREBLACK® based GDLs, respectively. By varying the wt. % of PEG, fuel cell performance is evaluated under relative humidity conditions of 60 and 100% using H2/O2 and H2/Air at 70 °C and the durability is also evaluated for the GDL samples without and with 30% PEG. The fuel cell performance of the GDL with 30% pore forming agent (with a pore volume of 1.72 cc.g−1) exhibited higher performance (444 and 432 mW cm−2 at 60 and 100% RH conditions, respectively using H2 and air) compared to that without pore forming agent (436 and 397 mW cm−2).

  • 10.
    Augusto, Ohara
    et al.
    Univ Sao Paulo, Inst Quim, Dept Bioquim, BR-5508000 Sao Paulo, Brazil..
    Goldstein, Sara
    Hebrew Univ Jerusalem, Chem Inst, IL-91904 Jerusalem, Israel..
    Hurst, James K.
    Oregon State Univ, Dept Biochem & Biophys, Corvallis, OR 97331 USA..
    Lind, Johan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Lymar, Sergei, V
    Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA..
    Merényi, Gabor
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Radi, Rafael
    Univ Republica, Dept Bioquim, Fac Med, Montevideo 11800, Uruguay.;Univ Republica, Ctr Free Rad & Biomed Res, Fac Med, Montevideo 11800, Uruguay..
    Carbon dioxide-catalyzed peroxynitrite reactivity - The resilience of the radical mechanism after two decades of research2019In: Free Radical Biology & Medicine, ISSN 0891-5849, Vol. 135, p. 210-215Article, review/survey (Refereed)
    Abstract [en]

    Peroxynitrite, ONOO-, formed in tissues that are simultaneously generating NO center dot and O-2(center dot-), is widely regarded as a major contributor to oxidative stress. Many of the reactions involved are catalyzed by CO2 via formation of an unstable adduct, ONOOC(O)O-, that undergoes O-O bond homolysis to produce NO2 center dot and CO3 center dot- radicals, whose yields are equal at about 0.33 with respect to the ONOO- reactant. Since its inception two decades ago, this radical-based mechanism has been frequently but unsuccessfully challenged. The most recent among these [Serrano-Luginbuehl et al. Chem. Res. Toxicol. 31: 721-730; 2018] claims that ONOOC(O)O- is stable, predicts a yield of NO2 center dot/CO3 center dot- of less than 0.01 under physiological conditions and, contrary to widely accepted viewpoints, suggests that radical generation is inconsequential to peroxynitrite-induced oxidative damage. Here we review the experimental and theoretical evidence that support the radical model and show this recently proposed alternative mechanism to be incorrect.

  • 11. Aung, S. H.
    et al.
    Zhao, L.
    Nonomura, K.
    Oo, T. Z.
    Zakeeruddin, S. M.
    Vlachopoulos, N.
    Sloboda, Tamara
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Svanström, S.
    Cappel, Ute B.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Hagfeldt, A.
    Grätzel, M.
    Toward an alternative approach for the preparation of low-temperature titanium dioxide blocking underlayers for perovskite solar cells2019In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 7, no 17, p. 10729-10738Article in journal (Refereed)
    Abstract [en]

    The anodic electrodeposition method is investigated as an alternative technique for the preparation of a titanium oxide (TiO 2 ) blocking underlayer (UL) for perovskite solar cells (PSCs). Extremely thin Ti IV -based films are grown from aqueous acidic titanium(iii) chloride in an electrochemical cell at room temperature. This precursor layer is converted to the UL (ED-UL), in a suitable state for PSC applications, by undertaking a sintering step at 450 °C for half an hour. PSCs with the composition of the light-absorbing material FA 0.85 MA 0.10 Cs 0.05 Pb(I 0.87 Br 0.13 ) 3 (FA and MA denote the formamidinium and methylammonium cations, respectively) based on the ED-UL are compared with PSCs with the UL of a standard type prepared by the spray-pyrolysis method at 450 °C from titanium diisopropoxide bis(acetylacetonate) (SP-UL). We obtain power conversion efficiencies (PCEs) of over 20% for mesoscopic perovskite devices employing both ED-ULs and SP-ULs. Slightly higher fill factor values are observed for ED-UL-based devices. In addition, ED-ULs prepared by the same method have also been applied in planar PSCs, resulting in a PCE exceeding 17%, which is comparable to that for similar PSCs with an SP-UL. The preparation of ED-ULs with a lower sintering temperature, 150 °C, has also been examined. The efficiency of a planar PSC incorporating this underlayer was 14%. These results point out to the possibility of applying ED-ULs in flexible planar PSCs in the future.

  • 12.
    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. 

  • 13.
    Barreiro Fidalgo, Alexandre
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Kumagai, Yuta
    Japan Atomic Energy Agency, Nuclear Science and Engineering Directorate, Nakagun, Japan.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    The role of surface-bound hydroxyl radicals in the reaction between H2O2 and UO22018In: Journal of coordination chemistry (Print), ISSN 0095-8972, E-ISSN 1029-0389, Vol. 71, no 11-13, p. 1799-1807Article in journal (Refereed)
    Abstract [en]

    In this work, we have studied the reaction between H2O2 and UO2 with particular focus on the nature of the hydroxyl radical formed as an intermediate. Experiments were performed to study the kinetics of H2O2 consumption and uranium dissolution at different initial H2O2 concentrations. The results show that the consumption rates at a given H2O2 concentration are different depending on the initial H2O2 concentration. This is attributed to an alteration of the reactive interface, likely caused by blocking of surface sites by oxidized U/surface-bound hydroxyl radicals. The dissolution yield given by the amount of dissolved uranium divided by the amount of consumed hydrogen peroxide was used to compare the different cases. For all initial H2O2 concentrations, the dissolution yield increases with reaction time. The final dissolution yield decreases with increasing initial H2O2 concentration. This is expected from the mechanism of catalytic decomposition of H2O2 on oxide surfaces. As the experiments were performed in solutions containing 10mM H2O2 and a strong concentration dependence was observed in the 0.2-2.0mM H2O2 concentration range, we conclude that the intermediate hydroxyl radical is surface bound rather than free.

  • 14.
    Bellander Jöcker, Ludvig
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Evaporation Based Hydrovoltaics of Whey Protein Nanofibril Materials2024Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In search of new power sources, scientists are investigating hydrovoltaic devices. This is a type of device that generates electricity from the direct interaction between water and a material. One such device is the evaporation-driven hydrovoltaic device. It consists of a porous material that is partially submerged into water, which rises though the material through capillary forces and evaporates from its surface. This creates a flow of water through the material which gives rise to an electric voltage, through an electrokinetic phenomenon called the streaming potential. This study investigates whetherhydro- and aerogels made from whey protein nanofibrils are a suitable porous material for these devices. As a by-product from the dairy industry, whey protein is cheap and renewable. The gels also have properties which are beneficial for generating a high streaming potential, such as hydrophilicity, small pores, and charged surface groups. In the study, two types of hydrogels were tested, one of which was treated with citric acid as a crosslinker in order to increase their stability in water. Aerogels were fabricated with three different initial concentrations of WPI. The gels were also frozen in three different ways before being freeze-dried to create aerogels. They were frozen at -80 °C in a freezer, at -196 °C by submersion in liquid nitrogen, and through directional freezing using liquid nitrogen, in order to vary their pore structure. When tested as hydrovoltaic devices, the gels did produce voltages, but no measurable currents. When measured over time, the voltages of most aerogels followed the same pattern with a fast initial increase followed by a slow decrease which levelled out towards some equilibrium voltage. The average maximum voltages for the aerogels varied between 73 and 149 mV, depending mostly on the freezing method. Varying the WPI concentration showed no significant effect on the voltage. Long term tests showed that the gels could sustain a voltage of around 60 mV for at least 19 hours. Hydrogels did not have an initial voltage peak but appeared to also produce an equilibrium voltage of around 60 mV, showing them to be competitive with the aerogels. It was thus shown that whey protein nanofibril materials could produce a low but significant hydrovoltaic potential, and that pore morphology was a significant factor in determining the voltage produced.

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  • 15.
    Berggren, Elin
    et al.
    Uppsala Univ, Dept Phys & Astron, Div X Ray Photon Sci, SE-75120 Uppsala, Sweden..
    Weng, Yi-Chen
    Uppsala Univ, Dept Phys & Astron, Div X Ray Photon Sci, SE-75120 Uppsala, Sweden..
    Li, Qifan
    Linköping Univ, Dept Sci & Technol, Lab Organ Elect, SE-60174 Norrköping, Sweden..
    Yang, Chi-Yuan
    Linköping Univ, Dept Sci & Technol, Lab Organ Elect, SE-60174 Norrköping, Sweden..
    Johansson, Fredrik
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. Sorbonne Univ, Inst Nanosci Paris, CNRS, INSP, F-75005 Paris, France..
    Cappel, Ute B.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Berggren, Magnus
    Linköping Univ, Dept Sci & Technol, Lab Organ Elect, SE-60174 Norrköping, Sweden..
    Fabiano, Simone
    Linköping Univ, Dept Sci & Technol, Lab Organ Elect, SE-60174 Norrköping, Sweden..
    Lindblad, Andreas
    Uppsala Univ, Dept Phys & Astron, Div X Ray Photon Sci, SE-75120 Uppsala, Sweden..
    Charge Transfer in the P(g42T-T): BBL Organic Polymer Heterojunction Measured with Core-Hole Clock Spectroscopy2023In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 127, no 49, p. 23733-23742Article in journal (Refereed)
    Abstract [en]

    The conductivity of organic polymer heterojunction devices relies on the electron dynamics occurring along interfaces between the acceptor and donor moieties. To investigate these dynamics with chemical specificity, spectroscopic techniques are employed to obtain localized snapshots of the electron behavior at selected interfaces. In this study, charge transfer in blends (by weight 10, 50, 90, and 100%) of p-type polymer P(g(4)2T-T) (bithiophene-thiophene) and n-type polymer BBL (poly(benzimidazo-benzo-phenanthroline)) was measured by resonant Auger spectroscopy. Electron spectra emanating from the decay of core-excited states created upon X-ray absorption in the donor polymer P(g(4)2T-T) were measured in the sulfur KL2,3L2,3 Auger kinetic energy region as a function of the excitation energy. By tuning the photon energy across the sulfur K-absorption edge, it is possible to differentiate between decay paths in which the core-excited electron remained on the atom with the core-hole and those where it tunneled away. Analyzing the competing decay modes of these localized and delocalized (charge-transfer) processes facilitated the computation of charge-transfer times as a function of excitation energy using the core-hole clock method. The electron delocalization times derived from the measurements were found to be in the as/fs regime for all polymer blends, with the fastest charge transfer occurring in the sample with an equal amount of donor and acceptor polymer. These findings highlight the significance of core-hole clock spectroscopy as a chemically specific tool for examining the local charge tunneling propensity, which is fundamental to understanding macroscopic conductivity. Additionally, the X-ray absorption spectra near the sulfur K-edge in the P(g(4)2T-T) polymer for different polymer blends were analyzed to compare molecular structure, orientation, and ordering in the polymer heterojunctions. The 50% donor sample exhibited the most pronounced angular dependence of absorption, indicating a higher level of ordering compared to the other weight blends. Our studies on the electron dynamics of this type of all-polymer donor-acceptor systems, in which spontaneous ground-state electron transfer occurs, provide us with critical insights to further advance the next generation of organic conductors with mixed electron-hole conduction characteristics suitable for highly stable electrodes of relevance for electronic, electrochemical, and optoelectronic applications.

  • 16.
    Bergman, Astrid
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Alternative Architectures of Quantum Dot Solar Cells2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Quantum dots are of great interest for producing solar cells due to the possibility of tuning the bandgap depending on the quantum dot size. In this Masters's thesis project alternative architectures of PbS quantum dot solar cells have been tested and the influences of different layers have been evaluated. First, a short reproducibility study of the PbS quantum dot solar cell was produced, where it could be seen that the fabricated solar cells gave low efficiencies compared to literature. A comparison of using ZnO or magnesium doped ZnO (MZO) was performed, where the solar cells using MZO performed better than the solar cells using ZnO. Furthermore, the influence of removing the hole compared to the electron transporting layer was tested, where the electron transporting layer proved to be essential for the solar cell to function while it still could function without the hole transporting layer. Additionally, an inverted solar cell structure was tested, but only produced solar cells with efficiencies below 0.09 %. It was also tested to use another ligand solution and solvent for the ligand exchange needed for the light-absorbing quantum dot layer in the solar cell. This was done using ammonium iodide for the ligand exchange to later disperse the quantum dots in propylene carbonate, although the films produced with the new ligand exchange were of poor quality and gave low-efficiency solar cells. Lastly, a short study of the annealing temperature of an MZO thin-film was realised, where it was found that the MZO crystallised at 250℃, 300℃, and 350℃ when annealed for 30 minutes.

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  • 17. Bergquist, Jonas
    et al.
    Emmer, Åsa
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Farbrot, Anne
    Turner, Charlotta
    Research and education in analytical chemistry — industrial and academic perspectives from a survey conducted in Sweden2023In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 415, no 12, p. 2151-2161Article in journal (Refereed)
  • 18.
    Bernin, Diana
    et al.
    Swedish NMR Ctr, Gothenburg, Sweden..
    Bialik, Erik
    Lund Univ, Div Theoret Chem, Lund, Sweden..
    Stenqvist, Bjorn
    Lund Univ, Div Theoret Chem, Lund, Sweden..
    Fang, Yuan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Ostlund, Asa
    SP Tech Res Inst Sweden, Stockholm, Sweden..
    Furo, Istvan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Lindman, Bjorn
    Lund Univ, Chem, Lund, Sweden..
    Lund, Mikael
    Lund Univ, Div Theoret Chem, Lund, Sweden..
    On the ionization of cellulose in aqueous alkali2017In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 253Article in journal (Other academic)
  • 19.
    Bhagavathiachari, Muthuraaman
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Elumalai, V.
    Gao, Jiajia
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Polymer-doped molten salt mixtures as a new concept for electrolyte systems in dye-sensitized solar cells2017In: ACS Omega, E-ISSN 2470-1343, Vol. 2, no 10, p. 6570-6575Article in journal (Refereed)
    Abstract [en]

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

  • 20. Bialik, Erik
    et al.
    Stenqvist, Bjorn
    Fang, Yuan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Ostlund, Asa
    Furo, Istvan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Lindman, Björn
    Lund, Mikael
    Bernin, Diana
    Ionization of Cellobiose in Aqueous Alkali and the Mechanism of Cellulose Dissolution2016In: The Journal of Physical Chemistry Letters, E-ISSN 1948-7185, Vol. 7, no 24, p. 5044-5048Article in journal (Refereed)
    Abstract [en]

    Cellulose, one of the most abundant renewable resources, is insoluble in most common solvents but dissolves in aqueous alkali under a narrow range of conditions. To elucidate the solubilization mechanism, we performed electrophoretic NMR on cellobiose, a subunit of cellulose, showing that cellobiose acts as an acid with two dissociation steps at pH 12 and 13.5. Chemical shift differences between cellobiose in NaOH and NaCl were estimated using 2D NMR and compared to DFT shift differences upon deprotonation. The dissociation steps are the deprotonation of the hemiacetal OH group and the deprotonation of one of four OH groups on the nonreducing anhydroglucose unit. MD simulations reveal that aggregation is suppressed upon charging cellulose chains in solution. Our findings strongly suggest that cellulose is to a large extent charged in concentrated aqueous alkali, a seemingly crucial factor for solubilization. This insight, overlooked in the current literature, is important for understanding cellulose dissolution and for synthesis of new sustainable materials.

  • 21.
    Blomdahl, Emil
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Synthesis and characterization of novel hybrid organic-inorganic materials2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

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

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

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

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

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

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  • 22.
    Bokore, Getachew E.
    et al.
    Int Ctr Insect Physiol & Ecol, POB 30772-00100, Nairobi, Kenya.;Maseno Univ, Sch Phys & Biol Sci, Dept Zool, Maseno, Kenya.;Ethiopian Publ Hlth Inst, POB 1242, Addis Ababa, Ethiopia..
    Svenberg, Linus
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Tamre, Richard
    Int Ctr Insect Physiol & Ecol, POB 30772-00100, Nairobi, Kenya.;Maseno Univ, Sch Phys & Biol Sci, Dept Zool, Maseno, Kenya..
    Onyango, Patrick
    Maseno Univ, Sch Phys & Biol Sci, Dept Zool, Maseno, Kenya..
    Bukhari, Tullu
    Int Ctr Insect Physiol & Ecol, POB 30772-00100, Nairobi, Kenya..
    Emmer, Åsa
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Fillinger, Ulrike
    Int Ctr Insect Physiol & Ecol, POB 30772-00100, Nairobi, Kenya..
    Grass-like plants release general volatile cues attractive for gravid Anopheles gambiae sensu stricto mosquitoes2021In: Parasites & Vectors, E-ISSN 1756-3305, Vol. 14, no 1, article id 552Article in journal (Refereed)
    Abstract [en]

    Background: Understanding the ecology and behaviour of disease vectors, including the olfactory cues used to orient and select hosts and egg-laying sites, are essential for the development of novel, insecticide-free control tools. Selected graminoid plants have been shown to release volatile chemicals attracting malaria vectors; however, whether the attraction is selective to individual plants or more general across genera and families is still unclear. Methods: To contribute to the current evidence, we implemented bioassays in two-port airflow olfactometers and in large field cages with four live graminoid plant species commonly found associated with malaria vector breeding sites in western Kenya: Cyperus rotundus and C. exaltatus of the Cyperaceae family, and Panicum repens and Cynodon dactylon of the Poaceae family. Additionally, we tested one Poaceae species, Cenchrus setaceus, not usually associated with water. The volatile compounds released in the headspace of the plants were identified using gas chromatography/mass spectrometry. Results: All five plants attracted gravid vectors, with the odds of a mosquito orienting towards the choice-chamber with the plant in an olfactometer being 2-5 times higher than when no plant was present. This attraction was maintained when tested with free-flying mosquitoes over a longer distance in large field cages, though at lower strength, with the odds of attracting a female 1.5-2.5 times higher when live plants were present than when only water was present in the trap. Cyperus rotundus, previously implicated in connection with an oviposition attractant, consistently elicited the strongest response from gravid vectors. Volatiles regularly detected were limonene, beta-pinene, beta-elemene and beta-caryophyllene, among other common plant compounds previously described in association with odour-orientation of gravid and unfed malaria vectors. Conclusions: The present study confirms that gravid Anopheles gambiae sensu stricto use chemical cues released from graminoid plants to orientate. These cues are released from a variety of graminoid plant species in both the Cyperaceae and Poaceae family. Given the general nature of these cues, it appears unlikely that they are exclusively used for the location of suitable oviposition sites. The utilization of these chemical cues for attract-and-kill trapping strategies must be explored under natural conditions to investigate their efficiency when in competition with complex interacting natural cues.

  • 23.
    Brinck, Tore
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Borrfors, Andre Nyberg
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    The Importance of Electrostatics and Polarization for Noncovalent Interactions: Ionic Hydrogen Bonds vs Ionic Halogen Bonds2022In: Journal of Molecular Modeling, ISSN 1610-2940, E-ISSN 0948-5023, Vol. 28, no 9, article id 275Article in journal (Refereed)
    Abstract [en]

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

  • 24.
    Brinck, Tore
    et al.
    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, Applied Physical Chemistry.
    Liljenberg, Magnus
    KTH.
    The use of quantum chemistry for mechanistic analyses of SeAR reactions2015In: Arene Chemistry: Reaction Mechanisms and Methods for Aromatic Compounds, wiley , 2015, p. 83-105Chapter in book (Other academic)
    Abstract [en]

    In this chapter, we review the current understanding of electrophilic aromatic substitution (SEAr) based on the latest experimental and quantum chemical studies. In addition, the most reliable and computationally effective methods for predicting regioselectivity and relative reactivity of SEAr are evaluated and described. The mechanism of nitration is analyzed in detail based on recent quantum chemical studies. In the gas phase, the reaction often has a contribution from a single-electron transfer (SET), and this contribution increases with the activation tendency of the aromatic substrate. The solution reaction lacks a driving force for SET, and the reaction has an early transition state that resembles an O-C coordinated π-complex in structure. In contrast, halogenation with molecular chlorine as the electrophile proceeds via a much later transition state that is more similar to the α-complex. Among the different reactivity descriptors that have been used to analyze regioselectivity and relative reactivity of SEAr, the average local ionization energy seems to have the best predictive power. As is generally the case for descriptor-based approaches, it is best suited for analyzing SEAr with early transition states. The α-complex approach has emerged as an alternative to reactivity descriptors for predicting regioselectivity. It is based on the assumption that the relative α-complex energies are similar to the corresponding transition state energies and thus reflect the positional selectivity for an aromatic substrate when reacting with a particular electrophile. The method provides quantitative predictions for halogenations but is not reliable for nitrations.

  • 25.
    Brinck, Tore
    et al.
    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, Applied Physical Chemistry. University of New Orleans.
    Murray, JS
    Politzer, P
    Octanol Water Partition-Coefficients Expressed In Terms Of Solute Molecular-Surface Areas And Electrostatic Potentials1993In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 58, no 25, p. 7070-7073Article in journal (Refereed)
    Abstract [en]

    For 70 molecules of various types and sizes, it is shown that their experimental octanol/water partition coefficients can be represented quantitatively in terms of the solute's molecular surface area in conjunction with two statistically-based quantities calculated from its surface electrostatic potential; the latter are the average deviation of the potential and its total variance. An ab initio SCF approach was used to compute STO-3G*-optimized geometries and STO-5G* electrostatic potentials.

  • 26.
    Brinck, Tore
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Nyberg Borrfors, Andre
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. KTH Royal Inst Technol, CBH, Dept Chem, Appl Phys Chem, SE-10044 Stockholm, Sweden..
    Electrostatics and polarization determine the strength of the halogen bond: a red card for charge transfer2019In: Journal of Molecular Modeling, ISSN 1610-2940, E-ISSN 0948-5023, Vol. 25, no 5, article id 125Article in journal (Refereed)
    Abstract [en]

    A series of 20 halogen bonded complexes of the types R-Br center dot center dot center dot Br- (R is a substituted methyl group) and R '-CC-Br center dot center dot center dot Br- are investigated at the M06-2X/6-311+G(d,p) level of theory. Computations using a point-charge (PC) model, in which Br- is represented by a point charge in the electronic Hamiltonian, show that the halogen bond energy within this set of complexes is completely described by the interaction energy (E-PC) of the point charge. This is demonstrated by an excellent linear correlation between the quantum chemical interaction energy and E-PC with a slope of 0.88, a zero intercept, and a correlation coefficient of R-2=0.9995. Rigorous separation of E-PC into electrostatics and polarization shows the high importance of polarization for the strength of the halogen bond. Within the data set, the electrostatic interaction energy varies between 4 and-18kcal mol(-1), whereas the polarization energy varies between -4 and-10kcal mol(-1). The electrostatic interaction energy is correlated to the sum of the electron-withdrawing capacities of the substituents. The polarization energy generally decreases with increasing polarizability of the substituents, and polarization is mediated by the covalent bonds. The lower (more favorable) E-PC of CBr4---Br- compared to CF3Br center dot center dot center dot Br- is found to be determined by polarization as the electrostatic contribution is more favorable for CF3Br center dot center dot center dot Br-. The results of this study demonstrate that the halogen bond can be described accurately by electrostatics and polarization without any need to consider charge transfer.

  • 27.
    Brinck, Tore
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Sahoo, Suman Kalyan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Anomalous π-backbonding in complexes between B(SiR3)3 and N2: catalytic activation and breaking of scaling relations2023In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 25, no 31, p. 21006-21019Article in journal (Refereed)
    Abstract [en]

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

  • 28.
    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, E-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.

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  • 29.
    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.

  • 30.
    Bubic, Sandra
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Kjellberg, Martin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Samuelsson, Ludvig
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Performance of SpheriCal® standards as calibrants for IgG glycopeptide analysis using MALDI-MS2022Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Our world is full of all different kinds of diseases - everything from the regular flu to more severe infections and chronic illnesses such as cancer and Alzheimer's disease. It is therefore of interest to be able to establish a diagnosis, and thus search possible treatments and cures. One way to do this is by using biomarkers and IgG (Immunoglobulin G) has shown to be suited as one. When using MALDI-TOF-MS (Matrix Assisted Laser Desorption/Ionization -Time of Flight - Mass Spectrometry), enrichment of the glycopeptides is required to provide an accurate analysis. Hence, by utilizing the strong hydrophilic interactions of glycans, which do not exist in non-glycopeptides, the glycosylated peptides can be enriched to achieve higher intensity in the spectra.

    That is why the aim of this bachelor’s degree project is to investigate if SpheriCal® calibrant standards are appropriate for the purpose of enabling and bettering the use of biomarkers in diagnostics and other medical areas when analyzing samples with MALDI-TOF-MS. Until now, other peptide-based calibrants have been used. Therefore, it has been desirable to compare the two to showcase whether SpheriCal® generates more accurate measurements.

    An initial step was glycosylation in order to obtain glycopeptides of IgG. Following that, tests were carried out with both internal- as well as external calibration methods with natural, purified and partly digested peptides and human samples of healthy- and COVID-19 infected patients. Furthermore, different matrices were tested, more specifically, DHB (2,5-dihydroxybenzoic acid) and HCCA (α-Cyano-4-hydroxycinnamic acid).

    To conclude the results, they showed that SpheriCal® calibrants generate high accuracy with small m/z (mass to charge) errors, for both internal- as well as external calibration methods, when analyzing IgG glycopeptides. For external calibration, SpheriCal®-APH showed significantly higher mass accuracy than conventionally used PCS in both HCCA and DHB.

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  • 31.
    Bui, Thi Diem Huong
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Brinck, Tore
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    p-block doped semi-metallic xenes as highly selective and efficient transition-metal free single atom catalysts for electrochemical CO reduction2023In: Journal of Materials Chemistry A, ISSN 2050-7488, E-ISSN 2050-7496, Vol. 12, no 4, p. 2110-2120Article in journal (Refereed)
    Abstract [en]

    The development of robust and inexpensive catalysts for the electrochemical CO reduction reaction (CORR) is key for sustainable production of valuable chemicals, yet it remains a long-standing challenge. Herein, we conduct a systematic theoretical investigation on p-block doping of semi-metallic xene monolayers to afford transition metal free catalysts for the CORR. Silicene (Si) and germanene (Ge) are suitable platforms for capturing the dopant (B/Al) to ensure high stability. Our single atom catalysts (SACs) are promising candidates for CORR due to their favorable initial CO adsorption and the selectivity of CO reduction over H2 evolution. B@Si, Al@Si, Al@Ge and B@Ge exhibit superior CORR catalytic activity with a limiting potential UL of 0.04, −0.39, −0.40, and −0.40 V, respectively. Notably, B@Si is identified as the best CORR electrocatalyst with an overpotential of less than 0.1 V. B@Si, Al@Si, Al@Ge exhibit high CORR selectivity towards CH3OH production, whereas B@Ge is predicted to form mainly CH4. The fundamental principles behind the outstanding CORR catalytic enhancement are disclosed by analyzing the structural and electronic configurations of two key intermediates, CO* and CHO*. CO* binds the dopant with moderate strength through a combination of σ-donation and π-backdonation unique for a transition metal free catalyst, whereas CHO* adsorbs strongly to the surface by the simultaneous binding to two neighboring atomic sites; consequently, the binding of the two intermediates breaks the scaling relation that limits the CORR activity of conventional catalysts. The optimal adsorption behaviors are attributed to the surface charge modulation induced by the substitutional doping. Hence, these findings may facilitate rational design of xene-based SACs for CORR and advance other catalytic applications.

  • 32.
    Bulone, Donatella
    et al.
    Institute of Biophysics, Consiglio Nazionale delle Ricerche, Palermo, Italy.
    Dispenza, Clelia
    Dipartimento di Ingegneria, Università degli Studi di Palermo, Palermo, Italy.
    Ditta, Lorena A.
    Institute of Biophysics, Consiglio Nazionale delle Ricerche, Palermo, Italy.
    Giacomazza, Daniela
    Institute of Biophysics, Consiglio Nazionale delle Ricerche, Palermo, Italy.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Antonietta Sabatino, Maria
    Dipartimento di Ingegneria, Università degli Studi di Palermo, Palermo, Italy.
    Lapasin, Romano
    University of Trieste, Trieste, Italy.
    Biagio, Pier L.San
    Institute of Biophysics, Consiglio Nazionale delle Ricerche, Palermo, Italy.
    Effect of gamma irradiation on HPC phase separation2023In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 122, no 3S1Article in journal (Refereed)
  • 33.
    Carlsson, Celice
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Fégeant, Benjamin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Svensson, Emelie
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Wiklund, Love
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    On the Selectivity of Radical Scavengers Used To Probe Hydroxyl Radical Formation in Heterogeneous Systems2022In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 126, no 30, p. 12435-12440Article in journal (Refereed)
    Abstract [en]

    Tris and methanol have been used quite extensively as probes for surface-bound hydroxyl radicals in heterogeneous systems, such as TiO2 photocatalysis and catalytic decomposition of H2O2. Recent studies have indicated that the selectivity for surface-bound hydroxyl radicals is questionable and that the yield of the stable detectable product, formaldehyde, may be different for different reactive species. In this work, we have explored the selectivity as well as the formaldehyde yield of these two probes by experimentally studying formaldehyde formation in homogeneous (gamma radiolysis) and heterogeneous (TiO2 photocatalysis) systems, where hydroxyl radicals and Br-2.- can be formed. The latter is formed in the reaction between hydroxyl radicals and Br- at relatively high concentrations of Br-. The experiments clearly show that the formaldehyde yield is reduced by 85% when comparing hydroxyl radicals and Br2 & BULL;- in a homogeneous methanol system and increased by 50% when making the same comparison for the homogeneous Tris system. The increased yield is attributed to a change in the reaction mechanism as Br2 & BULL;- is mainly expected to produce a nitrogen-centered radical cation, while the hydroxyl radical mainly produces carbon-centered radicals. The radical cation appears to produce formaldehyde with a higher yield. In the photocatalysis system, the trends are similar but even more emphasized. The rationale for this is discussed, as well as the suitability of methanol and Tris as probes for surface-bound hydroxyl radicals in heterogeneous systems.

  • 34.
    Casanova, Ana
    et al.
    Univ Murcia, Fac Chem, Dept Analyt Chem, E-30100 Murcia, Spain.;CNRS, CEMHTI, F-95071 Orleans, France..
    Cuartero, Maria
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Alacid, Yolanda
    Univ Murcia, Fac Chem, Dept Analyt Chem, E-30100 Murcia, Spain..
    Almagro, Carmen M.
    Univ Murcia, Fac Chem, Dept Analyt Chem, E-30100 Murcia, Spain..
    Garcia-Canovas, Francisco
    Univ Murcia, Fac Biol, Dept Biochem & Mol Biol A, E-30100 Murcia, Spain..
    Garcia, Maria S.
    Univ Murcia, Fac Chem, Dept Analyt Chem, E-30100 Murcia, Spain..
    Ortuno, Joaquin A.
    Univ Murcia, Fac Chem, Dept Analyt Chem, E-30100 Murcia, Spain..
    A sustainable amperometric biosensor for the analysis of ascorbic, benzoic, gallic and kojic acids through catechol detection. Innovation and signal processing2020In: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 145, no 10, p. 3645-3655Article in journal (Refereed)
    Abstract [en]

    In this work, we present a new catechol amperometric biosensor fabricated on the basis of naturally available enzymes in common mushrooms. The biosensor response mechanism comprises the reduction of the quinone exclusively produced in the oxidation of the catechol present in the sample, which is catalyzed by tyrosinase enzyme. The new catechol biosensor has demonstrated excellent analytical performance at increasing catechol concentrations in the sample solution, which includes superior reproducibility for several electrodes and long-term stability. On top of that, the biosensing element used in the fabrication is a sustainable material, of low-cost and presents an excellent lifetime of years. Whether the catechol biosensor is operating in the presence of a compound influencing the reactions underlying the amperometric response (such as ascorbic, benzoic, gallic and kojic acids), this serves as an analytical platform to detect these compounds in real samples. Particularly, we introduce herein for the first time different treatments to process the current signal of the biosensor pursuing the linearity needed for the analytical application in real samples. In this sense, the catechol biosensor has been successfully applied to the detection of benzoic, gallic and kojic acids in juices, teas and cosmetic products, respectively.

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  • 35.
    Cattaruzza, Martina
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Fang, Yuan
    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.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Liu, Fang
    Division of Materials and Manufacture, Department of Industrial and Materials Science, Chalmers University of Technology, SE-412 Gothenburg 96 Sweden.
    Johansson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Hybrid polymer-liquid lithium ion electrolytes: effect of porosity on the ionic and molecular mobility2023In: Journal of Materials Chemistry A, ISSN 2050-7488, E-ISSN 2050-7496, Vol. 11, no 13, p. 7006-7015Article in journal (Refereed)
    Abstract [en]

    Alternative electrolyte systems such as hybrid electrolytes are much sought after to overcome safety issues related to liquid electrolytes in lithium ion batteries (LIBs). Hybrid solid-liquid electrolytes (HEs) like the heterogeneous structural battery electrolyte (SBE) consist of two discrete co-existing phases prepared by polymerization-induced phase separation: one solid polymer phase providing mechanical integrity and the other one a percolating liquid ion-conducting phase. The present work investigates the ion and the solvent mobility in a series of HEs using morphological, electrochemical impedance and NMR spectroscopic methods. All the dried HEs exhibit a porous structure with a broad pore size distribution stretching down to <10 nm diameter. Penetration of the individual components of the solution, that is the ions and the solvent, in the solid polymer phase is demonstrated. Yet, it is the pores that are the main ion conduction channels in the liquid-saturated HEs and, in general, translational mobility is strongly dependent on the volume fraction and size of the pores and, thereby, on the initial liquid electrolyte content. We also observe that the translational mobility of solvent and the ions vary differently with the pore volume fraction. This finding is explained by the presence of small mesopores where the mobility strongly depends on the specific interactions of the molecular constituent with the pore wall. These interactions are inferred to be stronger for the EC/PC solvent than for the ions. This study shows how the morphology and the chemical composition of HEs affect the ionic and molecular transport in the system.

  • 36.
    Champenois, Elio G.
    et al.
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    H. List, Nanna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Ware, Matthew
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Britton, Mathew
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA; Department of Physics, Stanford University, Stanford, California 94305, USA.
    Bucksbaum, Philip H.
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA; Department of Physics, Stanford University, Stanford, California 94305, USA.
    Cheng, Xinxin
    SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Centurion, Martin
    Department of Physics and Astronomy, University of Nebraska Lincoln, Lincoln, Nebraska 68588, USA.
    Cryan, James P.
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Forbes, Ruaridh
    SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Gabalski, Ian
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA; Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
    Hegazy, Kareem
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA; Department of Physics, Stanford University, Stanford, California 94305, USA.
    Hoffmann, Matthias C.
    SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Howard, Andrew J.
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA; Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
    Ji, Fuhao
    SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Lin, Ming Fu
    SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Nunes, J. Pedro F.
    Department of Physics and Astronomy, University of Nebraska Lincoln, Lincoln, Nebraska 68588, USA.
    Shen, Xiaozhe
    SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Yang, Jie
    SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA; Department of Chemistry, Tsinghua University, Beijing 100084, China.
    Wang, Xijie
    SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Martinez, Todd J.
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA; Department of Chemistry, Stanford University, Stanford, California 94305, USA.
    Wolf, Thomas J.A.
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Femtosecond Electronic and Hydrogen Structural Dynamics in Ammonia Imaged with Ultrafast Electron Diffraction2023In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 131, no 14, article id 143001Article in journal (Refereed)
    Abstract [en]

    Directly imaging structural dynamics involving hydrogen atoms by ultrafast diffraction methods is complicated by their low scattering cross sections. Here we demonstrate that megaelectronvolt ultrafast electron diffraction is sufficiently sensitive to follow hydrogen dynamics in isolated molecules. In a study of the photodissociation of gas phase ammonia, we simultaneously observe signatures of the nuclear and corresponding electronic structure changes resulting from the dissociation dynamics in the time-dependent diffraction. Both assignments are confirmed by ab initio simulations of the photochemical dynamics and the resulting diffraction observable. While the temporal resolution of the experiment is insufficient to resolve the dissociation in time, our results represent an important step towards the observation of proton dynamics in real space and time.

  • 37.
    Chatre, Clément
    et al.
    Université de Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON UMR 5256, 69626 Villeurbanne, France.
    Ehret, Eric
    Université de Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON UMR 5256, 69626 Villeurbanne, France.
    Ondarçuhu, Thierry
    Université de Toulouse, CNRS, IMFT INPT-UPS, 31400 Toulouse, France.
    Steyer, Philippe
    Univ. Lyon, INSA de Lyon, Université Claude Bernard Lyon 1, CNRS, MATEIS, UMR 5510, 69621 Villeurbanne, France.
    Masenelli-Varlot, Karine
    Univ. Lyon, INSA de Lyon, Université Claude Bernard Lyon 1, CNRS, MATEIS, UMR 5510, 69621 Villeurbanne, France.
    Cadete Santos Aires, Francisco José
    Université de Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON UMR 5256, 69626 Villeurbanne, France;National Research Tomsk State University, LCR, 634050 Tomsk, Russia.
    Nozière, Barbara
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Influence of Surface-Active Substances and Substrates on the Wettability of Individual Aerosol Particles during Condensation by Environmental Scanning Electron Microscopy2023In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 39, no 8, p. 2957-2965Article in journal (Refereed)
    Abstract [en]

    The formation of liquid cloud droplets from aerosol particles in the Earth atmosphere is still under debate particularly because of the difficulties to quantify the importance of bulk and surface effects in these processes. Recently, single-particle techniques have been developed to access experimental key parameters at the scale of individual particles. Environmental scanning electron microscopy (ESEM) has the advantage to provide in situ monitoring of the water uptake of individual microscopic particles deposited on solid substrates. In this work, ESEM was used to compare droplet growth on pure ammonium sulfate (NH4)2SO4 and mixed sodium dodecyl sulfate/ammonium sulfate (SDS/(NH4)2SO4) particles and to explore the role of experimental parameters, such as the hydrophobic–hydrophilic character of the substrate, on this growth. With hydrophilic substrates, the growth on pure salt particles was strongly anisotropic, but this anisotropy was suppressed by the presence of SDS. With hydrophobic substrates, it is the wetting behavior of the liquid droplet that is impacted by the presence of SDS. The wetting behavior of the pure (NH4)2SO4 solution on a hydrophobic surface shows a step-by-step mechanism that can be attributed to successive pinning–depinning phenomena at the triple-phase line frontier. Unlike the pure (NH4)2SO4 solution, the mixed SDS/(NH4)2SO4 solution did not show such a mechanism. Therefore, the hydrophobic–hydrophilic character of the substrate plays an important role in the stability and dynamics of the liquid droplets’ nucleation by water vapor condensation. In particular, hydrophilic substrates are not suited for the investigation of the hygroscopic properties (deliquescence relative humidity (DRH) and hygroscopic growth factor (GF)) of particles. Using hydrophobic substrates, data show that the DRH of (NH4)2SO4 particles is measured within 3% accuracy on the RH and their GF could indicate a size-dependent effect in the micrometer range. The presence of SDS does not seem to modify the DRH and GF of (NH4)2SO4 particles. This study shows that the water uptake on deposited particles is a complex process but, once carefully taken into account, ESEM is a suitable technique to study them.

  • 38.
    Chaudhary, Himanshu
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Ferreira Fernandes, Ricardo M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. Centro de Investigação em Química, Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, s/n, Porto, P-4169-007, Portugal.
    Gowda, Vasantha
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Claessens, Mirelle M. A. E.
    Furo, Istvan
    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.
    Intrinsically disordered protein as carbon nanotube dispersant: How dynamic interactions lead to excellent colloidal stability2019In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 556, p. 172-179Article in journal (Refereed)
    Abstract [en]

    The rich pool of protein conformations combined with the dimensions and properties of carbon nanotubes create new possibilities in functional materials and nanomedicine. Here, the intrinsically disordered protein α-synuclein is explored as a dispersant of single-walled carbon nanotubes (SWNTs) in water. We use a range of spectroscopic methods to quantify the amount of dispersed SWNT and to elucidate the binding mode of α-synuclein to SWNT. The dispersion ability of α-synuclein is good even with mild sonication and the obtained dispersion is very stable over time. The whole polypeptide chain is involved in the interaction accompanied by a fraction of the chain changing into a helical structure upon binding. Similar to other dispersants, we observe that only a small fraction (15–20%) of α-synuclein is adsorbed on the SWNT surface with an average residence time below 10 ms

  • 39. Chaudhary, Himanshu
    et al.
    Meister, Sebastian
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Zetterberg, Henrik
    Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden..
    Löfblom, John
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Engineering.
    Lendel, Christofer
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Dissecting the structural organization of multiprotein amyloid aggregates using a bottom-up approach2020In: ACS Chemical Neuroscience, E-ISSN 1948-7193, Vol. 11, no 10, p. 1447-1457Article in journal (Refereed)
    Abstract [en]

    Deposition of fibrillar amyloid β (Aβ) in senile plaques is a pathological signature of Alzheimer's disease. However, senile plaques also contain many other components, including a range of different proteins. Although the composition of the plaques can be analyzed in post mortem tissue, knowledge of the molecular details of these multiprotein inclusions and their assembly processes is limited, which impedes the progress in deciphering the biochemical mechanisms associated with Aβ pathology. We here describe a bottom-up approach to monitor how proteins from human cerebrospinal fluid associate with Aβ amyloid fibrils to form plaque particles. The method combines flow cytometry and mass spectrometry proteomics and allowed us to identify and quantify 128 components of the captured multiprotein aggregates. The results provide insights in the functional characteristics of the sequestered proteins and reveal distinct interactome responses for the two investigated Aβ variants, Aβ(1-40) and Aβ(1-42). Furthermore, the quantitative data is used to build models of the structural organization of the multiprotein aggregates, which suggests that Aβ is not the primary binding target for all the proteins; secondary interactions account for the majority of the assembled components. The study elucidates how different proteins are recruited into senile plaques and establishes a new model system for exploring the pathological mechanisms of Alzheimer's disease from a molecular perspective.

  • 40.
    Chen, Chen
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Wiorek, Alexander
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Gomis Berenguer, Alicia
    Crespo, Gaston A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. UCAM-SENS, Universidad Católica San Antonio de Murcia, UCAM HiTech, Avda. Andres Hernandez Ros 1, 30107 Murcia, Spain, Avda. Andres Hernandez Ros 1.
    Cuartero, Maria
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. UCAM-SENS, Universidad Católica San Antonio de Murcia, UCAM HiTech, Avda. Andres Hernandez Ros 1, 30107 Murcia, Spain, Avda. Andres Hernandez Ros 1.
    Portable All-in-One Electrochemical Actuator-Sensor System for the Detection of Dissolved Inorganic Phosphorus in Seawater2023In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 95, no 8, p. 4180-4189Article in journal (Refereed)
    Abstract [en]

    We present a methodology for the detection of dissolved inorganic phosphorous (DIP) in seawater using an electrochemically driven actuator-sensor system. The motivation for this work stems from the lack of tangible solutions for the in situ monitoring of nutrients in water systems. It does not require the addition of any reagents to the sample and works under mild polarization conditions, with the sample confined to a thin-layer compartment. Subsequent steps include the oxidation of polyaniline to lower the pH, the delivery of molybdate via a molybdenum electrode, and the formation of an electroactive phosphomolybdate complex from DIP species. The phosphomolybdate complex is ultimately detected by either cyclic voltammetry (CV) or square wave voltammetry (SWV). The combined release of protons and molybdate consistently results in a sample pH < 2 as well as a sufficient excess of molybdate, fulfilling the conditions required for the stoichiometric detection of DIP. The current of the voltammetric peak was found to be linearly related to DIP concentrations between 1 and 20 μM for CV and 0.1 and 20 μM for SWV, while also being selective against common silicate interference. The analytical application of the system was demonstrated by the validated characterization of five seawater samples, revealing an acceptable degree of difference compared to chromatography measurements. This work paves the way for the future DIP digitalization in environmental waters by in situ electrochemical probes with unprecedented spatial and temporal resolution. It is expected to provide real-time data on anthropogenic nutrient discharges as well as the improved monitoring of seawater restoration actions.

  • 41.
    Chen, Pan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Terenzi, Camilla
    Wageningen Univ & Res, Wageningen, Netherlands..
    Furo, Istvan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Wohlert, Jakob
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Heterogeneous dynamics in cellulose from molecular dynamics simulations2019In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 257Article in journal (Other academic)
  • 42.
    Chen, Pan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Beijing Inst Technol, Sch Mat Sci & Engn, Beijing Engn Res Ctr Cellulose & Its Derivat, 5 South Zhongguancun St, Beijing 100081, Peoples R China..
    Terenzi, Camilla
    Wageningen Univ & Res, Lab Biophys, Stippeneng 4, NL-6708 WE Wageningen, Netherlands..
    Furo, Istvan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Wohlert, Jakob
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Quantifying Localized Macromolecular Dynamics within Hydrated Cellulose Fibril Aggregates2019In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 52, no 19, p. 7278-7288Article in journal (Refereed)
    Abstract [en]

    Molecular dynamics (MD) simulations of C-13 NMR longitudinal relaxation (T-1) distributions were recently established as a powerful tool for characterizing moisture adsorption in natural amorphous polymers. Here, such computational-experimental synergy is demonstrated in a system with intrinsically high structural heterogeneity, namely crystalline cellulose nanofibrils (CNFs) in highly hydrated aggregated state. In such a system, structure-function properties on the nanoscale remain largely uncovered by experimental means alone. In this work, broadly polydispersed experimental C-13 NMR T-1 distributions could be successfully reproduced in simulations and, for the first time, were decomposed into contributions from distinct molecular sources within the aggregated CNFs, namely, (i) the core and (ii) the less-accessible and accessible surface regions of the CNFs. Furthermore, within the surface groups structurally different sites such as (iii) residues with different hydroxymethyl orientations and (iv) center and origin chains could be discerned based on their distinct molecular dynamics. The MD simulations unravel a direct correlation between dynamical and structural heterogeneity at an atomistic-level resolution that cannot be accessed by NMR experiments. The proposed approach holds the potential to enable quantitative interpretation of NMR data from a range of multicomponent high-performance nanocomposites with significantly heterogeneous macromolecular structure.

  • 43.
    Chen, Pan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. Beijing Inst Technol, Sch Mat Sci & Engn, Beijing Engn Res Ctr Cellulose & Derivat, Beijing 100081, Peoples R China..
    Wohlert, Jakob
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Furo, Istvan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Water as an Intrinsic Structural Element in Cellulose Fibril Aggregates2022In: The Journal of Physical Chemistry Letters, E-ISSN 1948-7185, Vol. 13, no 24, p. 5424-5430Article in journal (Refereed)
    Abstract [en]

    While strong water association with cellulose in plant cell walls and man-made materials is well-established, its molecular scale aspects are not fully understood. The thermodynamic consequences of having water molecules located at the microfibril-microfibril interfaces in cellulose fibril aggregates are therefore analyzed by molecular dynamics simulations. We find that a thin layer of water molecules at those interfaces can be in a state of thermal equilibrium with water surrounding the fibril aggregates because such an arrangement lowers the free energy of the total system. The main reason is enthalpic: water at the microfibril- microfibril interfaces enables the cellulose surface hydroxyls to experience a more favorable electrostatic environment. This enthalpic gain overcomes the entropic penalty from strong immobilization of water molecules. Hence, those particular water molecules stabilize the cellulose fibril aggregates, akin to the role of water in some proteins. Structural and functional hypotheses related to this finding are presented.

  • 44.
    Cherednik, Avital
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Synthesis and Characterization of Materials for Carbon Based Hybrid Asymmetric Supercapacitor Electrodes2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Supercapacitors are energy storage devices that have drawn attention for the past decade. Some of the advantages of these devices are higher power density storage, extended life cycles, and fast charge and discharge times. However, supercapacitors are still limited in energy density compared to batteries. To obtain higher power and energy densities, a hybrid asymmetric supercapacitor is a good alternative. This device consists of one carbon-based electrode for non-faradaic reactions, and one carbon electrode combined with metal oxides for redox reactions. The material choice is important for the capability of a hybrid asymmetric supercapacitor. In this study, four different commercial carbons are investigated. The specific surface area, pore sizes, and morphology are compared. In addition, metal oxide nanoparticles MnO2 are synthesised, and crystal structure is investigated. Furthermore, the MnO2 particles are deposited on the four carbons and the growth of those is studied. Finally, the interaction between ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM[BF4]) as an electrolyte and the different carbons is studied.

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  • 45.
    Chernyshev, Alexander N.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Maier, Annika Carolin
    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.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Solubilization of Ni(II) and Eu(III) through complexation with a polyaryl ether based superplasticizer in alkaline media2021In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 263, article id 127686Article in journal (Refereed)
    Abstract [en]

    Solubilisation of Ni(II) and Eu(III) by complexation with a polyaryl ether based superplasticizer (PAE SP) in alkaline solutions was studied. The solubilization was investigated in two types of artificial cement pore waters simulating different stages of cement degradation at a pH of 12.4 and 13.3, respectively. The solubility of Ni(II) and Eu(III) increased as the concentration of superplasticizer was increased from 0.04 to 0.4 wt%. When the concentration of SP was increased from 0.4 to 4%, the solubility of Eu(III) and Ni(II) increased in the pore water with a pH of 12.4, while the concentrations decreased in the pore water with a pH of 13.3. This is explained by a more rapid degradation of the superplasticizer at higher pH leading to a release of phosphate groups and thereby precipitation of Eu(III) and Ni(II) as phosphates. Based on results of the solubilisation of Ni(II) and Eu(III) by model compounds (anisole and PEG 400) and 31P NMR spectroscopy it was confirmed that the complexation of the studied metals with the PAE polymer occurs via the phosphate group of the superplasticizer.

  • 46.
    Church, Tamara L.
    et al.
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden..
    Eriksson, Lars
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden..
    Leandri, Valentina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. RISE Chem Proc & Pharmaceut Dev, Forskargatan 20J, S-15136 Södertälje, Sweden.
    Gardner, James M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Hedin, Niklas
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden..
    A microporous polymer based on nonconjugated hindered biphenyls that emits blue light2024In: Scientific Reports, E-ISSN 2045-2322, Vol. 14, no 1, article id 14923Article in journal (Refereed)
    Abstract [en]

    Microporous organic polymers that have three-dimensional connectivity stemming from monomers with tetrahedral or tetrahedron-like geometry can have high surface areas and strong fluorescence. There are however few examples of such polymers based on hindered biaryls, and their fluorescence has not been studied. Hypothesizing that the contortion in a hindered biphenyl moiety would modulate the optical properties of a polymer built from it, we synthesized a meta-enchained polyphenylene from a 2,2',6,6'-tetramethylbiphenyl-based monomer, in which the two phenyl rings are nearly mutually perpendicular. The polymer was microporous with S-BET = 495 m(2) g(-1). The polymer absorbed near-UV light and emitted blue fluorescence despite the meta-enchainment that would have been expected to break the conjugation. A related copolymer, synthesized from 2,2',6,6'-tetramethylbiphenyl-based and unsubstituted biphenyl-based monomers, was microporous but not fluorescent.

  • 47.
    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.

  • 48. Ciftci, S.
    et al.
    Cánovas, Rocio
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Neumann, F.
    Paulraj, T.
    Nilsson, M.
    Crespo, Gaston A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Madaboosi, N.
    The sweet detection of rolling circle amplification: Glucose-based electrochemical genosensor for the detection of viral nucleic acid2020In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 151, article id 112002Article in journal (Refereed)
    Abstract [en]

    Herein, an isothermal padlock probe-based assay for the simple and portable detection of pathogens coupled with a glucose oxidase (GOx)-based electrochemical readout is reported. Infectious diseases remain a constant threat on a global scale, as in recurring pandemics. Rapid and portable diagnostics hold the promise to tackle the spreading of diseases and decentralising healthcare to point-of-care needs. Ebola, a hypervariable RNA virus causing fatalities of up to 90% for recent outbreaks in Africa, demands immediate attention for bedside diagnostics. The design of the demonstrated assay consists of a rolling circle amplification (RCA) technique, responsible for the generation of nucleic acid amplicons as RCA products (RCPs). The RCPs are generated on magnetic beads (MB) and subsequently, connected via streptavidin-biotin bonds to GOx. The enzymatic catalysis of glucose by the bound GOx allows for an indirect electrochemical measurement of the DNA target. The RCPs generated on the surface of the MB were confirmed by scanning electron microscopy, and among other experimental conditions such as the type of buffer, temperature, concentration of GOx, sampling and measurement time were evaluated for the optimum electrochemical detection. Accordingly, 125 μg mL−1 of GOx with 5 mM glucose using phosphate buffer saline (PBS), monitored for 1 min were selected as the ideal conditions. Finally, we assessed the analytical performance of the biosensing strategy by using clinical samples of Ebola virus from patients. Overall, this work provides a proof-of-concept bioassay for simple and portable molecular diagnostics of emerging pathogens using electrochemical detection, especially in resource-limited settings.

  • 49.
    Clarin, Leona
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Development and validation of an ultrafiltration-UHPLC-MS/MS method for the quantification of unbound Beta-Lactam antibiotics cefotaxime, piperacillin, cloxacillin and flucloxacillin in plasma2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Infections in critically ill patients are a problem for the healthcare system and at any one time, 70 % of all intensive care unit (ICU) patients are treated with antibiotics. Antibiotics bind toproteins in the blood, but only unbound drug can diffuse over capillary membranes and bindto the targeted receptor. Standard protein binding percentages for antibiotics have been developed from studies on healthy volunteers and dosing regimens for patients are adapted accordingly. The determination of the total concentration of antibiotics in patients’ bloodsamples is, based on the standard percentages, ordinarily representative for the pharmacological effect of the antibiotic. However, certain conditions that are common incritically ill patients can alter protein binding percentages, resulting in a larger or smaller unbound fraction. This in turn can result in toxicity or therapeutic failure.

    The aim of this project was to develop an analytical method for the determination of the unbound concentration of the Beta-Lactam antibiotics cefotaxime, flucloxacillin, cloxacillin and piperacillin in plasma. A method was successfully developed using ultrafiltration for the extraction of unbound analytes and ultra high performance liquid chromatography tandem mass spectrometry, UHPLC-MS/MS, for their quantification. The method was partly validated according to the European Medicines Agency’s guidelines on bioanalytical method validation.

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  • 50.
    Clark, Tim
    et al.
    Univ Erlangen Nurnberg, Comp Chem Ctr, Nagelsbachstr 25, D-91052 Erlangen, Germany..
    Brinck, Tore
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    The Conversation on Non-Covalent Interactions: an introduction2022In: Journal of Molecular Modeling, ISSN 1610-2940, E-ISSN 0948-5023, Vol. 28, no 9, article id 272Article in journal (Other academic)
1234567 1 - 50 of 494
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