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  • 301.
    Porsch, Christian
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Zhang, Yuning
    Östlund, Åsa
    Damberg, Peter
    Ducani, Cosimo
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Nyström, Andreas M.
    In Vitro Evaluation of Non-Protein Adsorbing Breast Cancer Theranostics Based on 19F-Polymer Containing Nanoparticles2013In: Particle & particle systems characterization, ISSN 0934-0866, E-ISSN 1521-4117, Vol. 30, no 4, 381-390 p.Article in journal (Refereed)
    Abstract [en]

    Eight fluorinated nanoparticles (NPs) are synthesized, loaded with doxorubicin (DOX), and evaluated as theranostic delivery platforms to breast cancer cells. The multifunctional NPs are formed by self-assembly of either linear or star-shaped amphiphilic block copolymers, with fluorinated segments incorporated in the hydrophilic corona of the carrier. The sizes of the NPs confirm that small circular NPs are formed. The release kinetics data of the particles reveals clear hydrophobic core dependence, with longer sustained release from particles with larger hydrophobic cores, suggesting that the DOX release from these carriers can be tailored. Viability assays and flow cytometry evaluation of the ratios of apoptosis/necrosis indicate that the materials are non-toxic to breast cancer cells before DOX loading; however, they are very efficient, similar to free DOX, at killing cancer cells after drug encapsulation. Both flow cytometry and confocal microscopy confirm the cellular uptake of NPs and DOX-NPs into breast cancer cells, and in vitro 19F-MRI measurement shows that the fluorinated NPs have strong imaging signals, qualifying them as a potential in vivo contrast agent for 19F-MRI.

  • 302.
    Prakobna, Kasinee
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Berthold, Fredrik
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Architecture of ultra-high porous honeycombs prepared from core-shell nanocellulose: Structure and mechanical performance2014In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 247, 160-CELL- p.Article in journal (Other academic)
  • 303.
    Prideaux, Sonja
    KTH, School of Chemical Science and Engineering (CHE).
    Speciation and bioavailability of chromium and nickel in Swedish freshwater: For improved assessments in life-cycle analysis (LCA)2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Metals are used in every part of our modern society. As population and wealth increases, so does the demand for metals and metal products. This inherently leads to metal emissions, from the process of mining and producing to usage and disposal. Emissions that may possess a threat to human health and the environment. One method to assess possible impacts over the entire chain ‘from cradle to grave’ is life-cycle assessment (LCA). This method is used today by regulatory instances as well as industry to evaluate total environmental impact of a certain product or process. Toxicity impact of chemical emissions is one part of the LCA analysis, calculated as the product of the fate of the chemical, the exposure routes of the chemical and the effect of the exposure. When it comes to metal emissions, evaluating exposure is not trivial, since it depends on the speciation of the metal whether or not an organism will be exposed. In freshwater ecosystems, the sum of all the metal species that are available for biological uptake are referred to as the bioavailable fraction. The speciation pattern, and thus the size of the bioavailable fraction of a metal, is largely dependent on ambient water chemistry, so that regional differences will be observed. Recent improvements in the LCA methodology have incorporated calculations of the bioavailable fraction of metal emissions, as well as regional variability by the use of seven European water types. However, Swedish freshwater is normally softer, with a lower pH and a higher concentration of metals than the European water types. There is therefore a need to evaluate whether the existing system is applicable to Swedish water chemistry, or if there is a need for further implementations.

    To this background, the aim of this project has been to evaluate the speciation and bioavailability of chromium and nickel, in a case study of emissions into a freshwater relevant for the Swedish steel industry. Specifically, bioavailability factors (BFs) for the two metals were sought, for implementation in the LCA methodology. To accomplish this, computer modelling using Visual MINTEQ and WHAM has been performed, as well as laboratory experiments. In addition, metal release from slag particles has been investigated.

    The results show that the bioavailability of chromium is dominated by the oxidation state of the metal. In the form of Cr(III), it will mainly form insoluble complexes, and the BF is as low as 5·10-5. In the form of Cr(VI) the BF is 0.64. Hence a large amount will be in the largely mobile and bioavailable fraction. This is also the most toxic form of chromium. It is thus very important when assessing chromium emissions to know the oxidation state of the metal. Nickel will mainly be removed from the bioavailable fraction by formation of strong complexes with organic matter. The BF of Ni was established as 0.37 for this case study. Modelling in WHAM gave results in accordance with laboratory results, while Visual MINTEQ seemed to underestimate the BF. Metal content was low in the slag, and the release hardly detectable. However, the results suggest that a large fraction of the released Cr, although low, is in the form of Cr(VI).

  • 304. Qian, Z.
    et al.
    Raghubanshi, H.
    Sterlin Leo Hudson, M.
    Srivastava, O. N.
    Liu, X.
    Ahuja, Rajeev
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Uppsala University, Sweden.
    Ab initio insight into graphene nanofibers to destabilize hydrazine borane for hydrogen release2017In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 669, 404-411 p.Article in journal (Refereed)
    Abstract [en]

    We report the potential destabilizing effects of graphene nanofibers on the hydrogen release property of hydrazine borane via state-of-the-art ab initio calculations for the first time. Interactions of a hydrazine borane cluster with two types of graphene patch edges which exist abundantly in our synthesized graphene nanofibers have been investigated. It is found that both zigzag and armchair edges can greatly weaken the H-host bonds (especially the middle N[sbnd]H bond) of hydrazine borane. The dramatic decrease in hydrogen removal energy is caused by the strong interaction between hydrazine borane and the graphene patch edges concerning the electronic charge density redistribution.

  • 305. Quignon, Benoit
    et al.
    Pilkington, Georgia A.
    Thormann, Esben
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Ashfold, Michael N. R.
    Mattia, Davide
    Leese, Hannah
    Davis, Sean A.
    Briscoe, Wuge H.
    Sustained Frictional Instabilities on Nanodomed Surfaces: Stick Slip Amplitude Coefficient2013In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 7, no 12, 10850-10862 p.Article in journal (Refereed)
    Abstract [en]

    Understanding the frictional properties of nanostructured surfaces is important because of their increasing application in modem minlaturized devices. In this work, lateral force microscopy was used to study the frictional properties between AFM nanotip and surfaces bearing well-defined ranging from tens to hundreds of nanometers. Our results show that the average lateral force varied linearly with applied load, as described by Amontons' first law of friction, although no direct correlation between the sample topographic properties and their measured friction coeffidents was identified. Furthermore, all the nanodomed textures exhibited pronounced osdllations in the shear traces, similar to the dassic stick slip behavior, under all the shear velocities and load regimes studied. That is, the nanotextured topography led to sustained frictional instabilities, effectively with no contact frictional sliding. The amplitude of the stick slip oscillations, ab was found to correlate with the topographic properties of the surfaces and scale linearly with the applied load. In line with the friction coefficient, we define the slope of this linear plot as the stick slip amplitude coeffident (SSAC). We suggest that such stick slip behaviors are characteristics of surfaces with nanotextures and that such local frictional instabilities have important implications to surface damage and wear. We thus propose that the shear characteristics of the nanodomed surfaces cannot be fully described by the framework of Amontons' laws of friction and that additional parameters (e.g., a, and SSAQ are required, when their friction, lubrication, and wear properties are important considerations in related nanodevices.

  • 306. Rasheed, Faiza
    et al.
    Hedenqvist, Mikael S.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Kuktaite, Ramune
    Plivelic, Tomas S.
    Gallstedt, Mikael
    Johansson, Eva
    Mild gluten separation - A non-destructive approach to fine tune structure and mechanical behavior of wheat gluten films2015In: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 73, 90-98 p.Article in journal (Refereed)
    Abstract [en]

    Despite the increasing production of wheat gluten (WG) for industrial use, minor attention has been given to the impact of the separation procedure on the gluten quality. The purpose of the present study was to probe the effect of the separation treatments (harsh vs mild) on gluten structure, morphology, and performance in bio-based films. The harshly separated industrial WG showed aggregated and pre-cross linked structure in the starting material most likely due to shear forces during gluten separation from flour and heat effect during the drying procedures. Further, when the harshly separated WG was processed into films the pre-crosslinked starting material restricted new crosslinks formation and structural rearrangements at nano-scale. The mechanical integrity of the film was also affected resulting in films with low Young's modulus and strength. WG (from cultivars Diskette, Puntari, and Sleipner) recovered from mild separation showed relatively "native" non-destructed crosslinking pattern and not previously observed structural morphology at nano-scale. When processed into films the mildly separated WG showed well polymerized intimately crosslinked proteins both with disulfide and other covalent crosslinks. The nano-scale morphology showed lamellar and hexagonal arrangements, not reported so far in any study. The structural rearrangements among films from mildly separated WG resulted in materials with improved mechanical integrity as compared to films from harshly separated WG. The present study showed that the quality of WG is significantly affected by the separation procedure which also affects protein polymerization, nano-scale morphology, and tensile properties of films.

  • 307. Rasheed, Faiza
    et al.
    Newson, William R.
    Plivelic, Tomas S.
    Kuktaite, Ramune
    Hedenqvist, Mikael S.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Gällstedt, Mikael
    Johansson, Eva
    Structural architecture and solubility of native and modified gliadin and glutenin proteins: non-crystalline molecular and atomic organization2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 4, 2051-2060 p.Article in journal (Refereed)
    Abstract [en]

    Wheat gluten (WG) and its components, gliadin and glutenin proteins, form the largest polymers in nature, which complicates the structural architecture of these proteins. Wheat gluten, gliadin and glutenin proteins in unmodified form showed few secondary structural features. Structural modification of these proteins using heat, pressure and the chemical chaperone glycerol resulted in a shift to organized structure. In modified gliadin, nano-structural molecular arrangements in the form of hexagonal closed packed (HCP) assemblies with lattice parameter of (58 angstrom) were obvious together with development of intermolecular disulphide bonds. Modification of glutenin resulted in highly polymerized structure with proteins linked not only by disulphide bonds, but also with other covalent and irreversible bonds, as well as the highest proportion of beta-sheets. From a combination of experimental evidence and protein algorithms, we have proposed tertiary structure models of unmodified and modified gliadin and glutenin proteins. An increased understanding of gliadin and glutenin proteins structure and behavior are of utmost importance to understand the applicability of these proteins for various applications including plastic materials, foams, adhesives, films and coatings.

  • 308.
    Rehn, Dirk Robert
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Dreuw, Andreas
    Norman, Patrick
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Resonant Inelastic X-ray Scattering Amplitudes and Cross Sections in the Algebraic Diagrammatic Construction/Intermediate State Representation (ADC/ISR) Approach2017In: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 13, no 11, 5552-5559 p.Article in journal (Refereed)
    Abstract [en]

    A scheme has been derived and implemented to gain computational access to the full electronic part of the Kramers-Heisenberg-Dirac (KHD) expression for resonant and nonresonant inelastic scattering amplitudes. Our implementation of this scheme is based on the complex polarization propagator in the algebraic diagrammatic construction (ADC) framework and within its intermediate state representation (ISR). The hierarchy of the second- and third-order ADC/ISR computational schemes known as ADC(2), ADC(2)-x, and ADC(3/2) is considered, and the calculated resonant inelastic X-ray scattering (RIXS) amplitudes and transition strengths for water are in excellent agreement with recent experimental data.

  • 309.
    Renberg, Björn
    et al.
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    Andersson-Svahn, Helene
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    Hedhammar, My
    Mimicking silk spinning in a microchip2014In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 195, 404-408 p.Article in journal (Refereed)
    Abstract [en]

    Nature's high performance material, spider silk, is formed during the passage of a protein solution through a spinning duct. Herein we present a microfluidic device with dual laminar mobile phases where silk formation can be mimicked and investigated. Recombinant miniature spidroins, with or without the pH-switching N-terminal domain, were used to investigate spinning conditions into silk-like fibers using this setup.

  • 310.
    Rexed, Ivan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    della Pietra, Massimiliano
    University of Perugia.
    McPhail, Stephen
    ENEA.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lagergren, Carina
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Molten carbonate fuel cells for CO2 separation and segregation by retrofitting existing plants - An analysis of feasible operating windows and first experimental findings2015In: International Journal of Greenhouse Gas Control, ISSN 1750-5836, E-ISSN 1878-0148, Vol. 35, 120-130 p.Article in journal (Refereed)
    Abstract [en]

    Molten carbonate fuel cells (MCFC) used as active carbon dioxide concentrator units are a promising solution to reduce greenhouse gas (GHG) emissions from traditional combustion plants. The cell reaction transfers carbonate ions from the cathode to the anode and allows the fuel cell to simultaneously produce power and separate CO2 from a stream of flue gas. Carbon dioxide separation is of high interest for use in natural gas combined cycles and coal gas combustion plants, as a large part of anthropogenic CO2 worldwide originates from such installations. The flue gas from these types of combustion technologies typically contains 3-15% CO2, which is in the lower operational range of the MCFC. The aim of this work was to investigate the possibility to retrofit existing power plants with MCFC to reduce the total release of CO2 without necessarily reducing the power output, and to understand which kind of power plant could have the major benefits with an MCFC retrofitting. The performance of lab scale MCFC fed with simulated flue gas was evaluated, and a number of operational parameters, such as utilization factor and cathode humidification were varied to study the effect on fuel cell performance. The results show that it is feasible to operate the MCFC as a CO2 separator for simulated gas turbine flue gas; however, the voltage drop due to low CO2 concentration may restrict the operating window depending on various operating conditions.

  • 311.
    Rexed, Ivan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lagergren, Carina
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Performance degradation of Molten Carbonate Fuel Cells caused by SO2 in simulated flue gasManuscript (preprint) (Other academic)
    Abstract [en]

    The effect on MCFC performance degradation SO2 contaminant at the cathode, in combination with operating the fuel cell with CO2 lean oxidant gas, simulating combustion flue gas, was evaluated. Of special focus was the effect of electrolyte degradation.

     Measurements were performed to test the effect of SO2 in the oxidant gas stream, followed by regeneration with clean gas. A 3cm2 button cell MCFC allowing active electrolyte management by refilling was for 1500h to benchmark the performance degradation without contaminants. In order to study the poisoning effect of SO2 entering the fuel cell gas, the MCFC was operated for 250h with the addition of 18ppm SO2 in the oxidant gas. Electrolyte was added after 1500h of benchmark operation and after 250h of contaminant operation. The addition of 18ppm SO2 greatly accelerated the performance degradation of the fuel cell. Measurements showed that the internal resistance was the single factor which was most affected by the SO2 poisoning, and that the performance degradation after 250h was not reversed by regeneration with clean gas, but with the addition of fresh electrolyte. This led us to conclude that SO2 in oxidant gas leads to an accelerated loss of electrolyte and subsequent decrease in conductivity of the electrolyte, causing loss of performance and meeting end of life criteria after relatively short operational time. Other factors, such as poisoning of the anode and corrosion of cathode side current collectors, were also detected. 

  • 312. Riedlinger, Michael D.
    et al.
    Corkery, Robert W.
    Naturalnano Inc.
    Cosmetic skincare applications employing mineral-derived tubules for controlled release2005Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    Compositions and methods pertaining to the topical treatment of skin are disclosed. The present invention relates to topical compositions for regulating the condition of skin, especially for regulating visible and/or tactile discontinuities in skin associated with skin aging, environmental affects and the like. One embodiment of the present invention relates to improving skin with compositions containing one or more non-volatile, slowly absorbed, liquid or semi-liquid organic substances (active agents) via controlled release of active agents associated with mineral-derived tubules such as halloysite nanotubules. For example, the active agents, in the form of organic substances may include vitamin compounds and glycerin, among others.

  • 313. Ringholm, Magnus
    et al.
    Bast, Radovan
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. KTH, School of Computer Science and Communication (CSC), Centres, Centre for High Performance Computing, PDC.
    Oggioni, Luca
    Ekstrom, Ulf
    Ruud, Kenneth
    Analytic calculations of hyper-Raman spectra from density functional theory hyperpolarizability gradients2014In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 141, no 13, 134107- p.Article in journal (Refereed)
    Abstract [en]

    We present the first analytic calculations of the geometrical gradients of the first hyperpolarizability tensors at the density-functional theory (DFT) level. We use the analytically calculated hyperpolarizability gradients to explore the importance of electron correlation effects, as described by DFT, on hyper-Raman spectra. In particular, we calculate the hyper-Raman spectra of the all-trans and 11-cis isomers of retinal at the Hartree-Fock (HF) and density-functional levels of theory, also allowing us to explore the sensitivity of the hyper-Raman spectra on the geometrical characteristics of these structurally related molecules. We show that the HF results, using B3LYP-calculated vibrational frequencies and force fields, reproduce the experimental data for all-trans-retinal well, and that electron correlation effects are of minor importance for the hyper-Raman intensities.

  • 314.
    Rinkevicius, Zilvinas
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. KTH, Centres, SeRC - Swedish e-Science Research Centre.
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Rosal Sandberg, Jaime Axel
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Non-linear optical properties of molecules in heterogeneous environments: a quadratic density functional/molecular mechanics response theory2014In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, no 19, 8981-8989 p.Article in journal (Refereed)
    Abstract [en]

    We generalize a density functional theory/molecular mechanics approach for heterogeneous environments with an implementation of quadratic response theory. The updated methodology allows us to address a variety of non-linear optical, magnetic and mixed properties of molecular species in complex environments, such as combined metallic, solvent and confined organic environments. Illustrating calculations of para-nitroaniline on gold surfaces and in solution reveals a number of aspects that come into play when analyzing second harmonic generation of such systems - such as surface charge flow, coupled surface-solvent dynamics and induced geometric and electronic structure effects of the adsorbate. Some ramifications of the methodology for applied studies are discussed.

  • 315.
    Rokhas, Maria Khihon
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Mikkonen, Saara
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Beyer, J.
    Jacksén, Johan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Emmer, Åsa
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    CE analysis of single wood cells performing hydrolysis and preconcentration in open microchannels2014In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 35, no 2-3, 450-457 p.Article in journal (Refereed)
    Abstract [en]

    In the present work, monosaccharides from pulp samples and single wood fibers were analyzed with CE, using indirect detection due to the lack of chromophores on the monosaccharides. The hydrolysis degradation of cellulose and hemicellulose into monosaccharides was performed using TFA, either in bulk scale or in microscale. In the microscale, one single wood fiber was hydrolyzed in an open microchannel manufactured on a silicon microchip with the dimensions 50 μm × 50 μm (length 1 or 3 cm). The low monosaccharide amounts derived from a single fiber implied that a preconcentration step was necessary to increase the detectability. Thus, an electromigration preconcentration of the hydrolyzed samples was performed within the microchannel, which resulted in a significantly enhanced signal intensity of the monosaccharides. In addition to the experimental study, computer simulations were performed regarding the preconcentration step of monosaccharides. The results from these simulations correlated well with the experimental results.

  • 316.
    Rosal Sandberg, Jaime Axel
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Rinkevicius, Zilvinas
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. KTH, Centres, SeRC - Swedish e-Science Research Centre.
    New recurrence relations for analytic evaluationof two-electron repulsion integrals over highly contracted gaussian-type orbitalsManuscript (preprint) (Other academic)
  • 317.
    Rosal Sandberg, Jaime Axel
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Rinkevicius, Zilvinas
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. KTH, Centres, SeRC - Swedish e-Science Research Centre.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Efficient time dependent density functional theory calculations using general contraction basis setsManuscript (preprint) (Other academic)
  • 318. Rubio-Magnieto, Jenifer
    et al.
    Gebremedhn Azene, Elias
    Knoops, Jeremie
    Knippenberg, Stefan
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. University of Mons, Belgium.
    Delcourt, Cecile
    Thomas, Amandine
    Richeter, Sebastien
    Mehdi, Ahmad
    Dubois, Philippe
    Lazzaroni, Roberto
    Beljonne, David
    Clement, Sebastien
    Surin, Mathieu
    Self-assembly and hybridization mechanisms of DNA with cationic polythiophene2015In: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 11, no 2, 6460-6471 p.Article in journal (Refereed)
    Abstract [en]

    The combination of DNA and pi-conjugated polyelectrolytes (CPEs) represents a promising approach to develop DNA hybridization biosensors, with potential applications for instance in the detection of DNA lesions and single-nucleotide polymorphisms. Here we exploit the remarkable optical properties of a cationic poly[3-(6'-(trimethylphosphonium)hexyl)thiophene-2,5-diyl] (CPT) to decipher the self-assembly of DNA and CPT. The ssDNA/ CPT complexes have chiroptical signatures in the CPT absorption region that are strongly dependent on the DNA sequence, which we relate to differences in supramolecular interactions between the thiophene monomers and the various nucleobases. By studying DNA-DNA hybridization and melting processes on preformed ssDNA/ CPT complexes, we observe sequence-dependent mechanisms that can yield DNA-condensed aggregates. Heating-cooling cycles show that non-equilibrium mixtures can form, noticeably depending on the working sequence of the hybridization experiment. These results are of high importance for the use of pi-conjugated polyelectrolytes in DNA hybridization biosensors and in polyplexes.

  • 319.
    Rutland, Mark W.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. SP Tech Res Inst, Sweden.
    Liljeblad, Jonathan D. F.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Tyrode, Eric
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Thormann, Esben
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Dublanchet, Ann-Claude
    Luengo, Gustavo
    Johnson, C. Magnus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Long chained fatty acid monolayers: Influence of methyl branching2014In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 247, 61-COLL- p.Article in journal (Other academic)
  • 320. Sacui, Iulia A.
    et al.
    Nieuwendaal, Ryan C.
    Burnett, Daniel J.
    Stranick, Stephan J.
    Jorfi, Mehdi
    Weder, Christoph
    Foster, E. Johan
    Olsson, Richard T.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Gilman, Jeffery W.
    Comparison of the Properties of Cellulose Nanocrystals and Cellulose Nanofibrils Isolated from Bacteria, Tunicate, and Wood Processed Using Acid, Enzymatic, Mechanical, and Oxidative Methods2014In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 6, no 9, 6127-6138 p.Article in journal (Refereed)
    Abstract [en]

    This work describes the measurement and comparison of several important properties of native cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs), such as crystallinity, morphology, aspect ratio, and surface chemistry. Measurement of the fundamental properties of seven different CNCs/CNFs, from raw material sources (bacterial, tunicate, and wood) using typical hydrolysis conditions (acid, enzymatic, mechanical, and 2,2,6,6-tetramethylpiperidiny1-1-oxyl (TEMPO)-mediated oxidation), was accomplished using a variety of measurement methods. Atomic force microscopy (AFM), transmission electron microscopy (TEM), and C-13 cross-polarization magic angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectroscopy were used to conclude that CNCs, which are rodlike in appearance, have a higher crystallinity than CNFs, which are fibrillar in appearance. CNC aspect ratio distributions were measured and ranged from 148 +/- 147 for tunicate-CNCs to 23 +/- 12 for wood-CNCs. Hydrophobic interactions, measured using inverse gas chromatography (IGC), were found to be an important contribution to the total surface energy of both types of cellulose. In all cases, a trace amount of naturally occurring fluorescent compounds was observed after hydrolysis. Confocal and Raman microscopy were used to confirm that the fluorescent species were unique for each cellulose source, and demonstrated that such methods can be useful for monitoring purity during CNC/CNF processing. This study reveals the broad, tunable, multidimensional material space in which CNCs and CNFs exist.

  • 321. Saigal, Trishna
    et al.
    Riley, John K.
    Golas, Patricia Lynn
    Bodvik, Rasmus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Claesson, Per Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Matyjaszewski, Krzysztof
    Tilton, Robert D.
    Poly(Ethylene Oxide) Star Polymer Adsorption at the Silica/Aqueous Interface and Displacement by Linear Poly(Ethylene Oxide)2013In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 29, no 12, 3999-4007 p.Article in journal (Refereed)
    Abstract [en]

    Multiarm star copolymers with approximately 460 poly(ethylene oxide) (PEO) arms that have a degree of polymerization N = 45 were synthesized via atom transfer radical polymerization (ATRP) of PEO-methacrylate macro-monomers in the presence of divinyl benzene cross-linkers. These are an example of molecular or nanoparticulate brushes that are of interest as steric stabilizers or boundary lubrication agents when adsorbed from solution to a solid/aqueous interface. We use ellipsometry to measure adsorption isotherms at the silica/aqueous interface for PEO star polymers and linear PEO chains having molecular weights comparable either to the star polymer or to the individual arms. The compactness of the PEO star polymers (molecular weight 1.2 x 10(6)) yields a saturation surface excess concentration that is approximately 3.5 times greater than that of the high molecular weight (1 X 10(6)) linear PEO. Adsorption of low molecular weight (6000) linear PEO was below the detection limit. Competitive adsorption experiments were conducted with ellipsometry, complemented by independent quartz crystal microbalance with dissipation (QCM-D) measurements. Linear PEO (high molecular weight) displaced preadsorbed PEO star polymers over the course of approximately 1.5 h, to form a mixed adsorbed layer having not only a significantly lower overall polymer surface excess concentration, but also a significantly greater amount of hydrodynamically entrapped water. Challenging a preadsorbed linear PEO (high molecular weight) layer with PEO star polymers produced no measurable change in the overall polymer surface excess concentration, but changes in the QCM-D energy dissipation and resonance frequency suggested that the introduction of PEO star polymers caused a slight swelling of the layer with a correspondingly small increase in entrapped water content.

  • 322.
    Saito, Tsuguyuki
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Kuramae, R.
    Wohlert, Jakob
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Isogai, A.
    An ultrastrong nanofibrillar biomaterial: The strength of single cellulose nanofibrils revealed via sonication-induced fragmentation2013In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 14, no 1, 248-253 p.Article in journal (Refereed)
    Abstract [en]

    We report the mechanical strength of native cellulose nanofibrils. Native cellulose nanofibrils, purified from wood and sea tunicate, were fully dispersed in water via a topochemical modification of cellulose nanofibrils using 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO) as a catalyst. The strength of individual nanofibrils was estimated based on a model for the sonication-induced fragmentation of filamentous nanostructures. The resulting strength parameters were then analyzed based on fracture statistics. The mean strength of the wood cellulose nanofibrils ranged from 1.6 to 3 GPa, depending on the method used to measure the nanofibril width. The highly crystalline, thick tunicate cellulose nanofibrils exhibited higher mean strength of 3-6 GPa. The strength values estimated for the cellulose nanofibrils in the present study are comparable with those of commercially available multiwalled carbon nanotubes.

  • 323.
    Sandberg, Jan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Le Bozec, N.
    Frensh Corrosion Insitute, Brest, France.
    Corrosion-induced copper runoff from naturally and pre-patinated copper, with and without surface treatments, in a marine environment2005In: Proc. 16th International Corrosion Congress, 2005Conference paper (Other academic)
  • 324.
    Sauge, Sebastien
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Antiprotonic helium atomcules2012In: From Quantum Chemistry To Astrophysics: A Tribute To Pierre Valiron, EDP Sciences, 2012, 03002- p.Conference paper (Refereed)
    Abstract [en]

    About 3% of antiprotons (p̄) stopped in helium are long-lived with microsecond lifetimes, against picoseconds in all other materials. This unusual longevity has been ascribed to the trapping of p̄ on metastable bound states in p̄He+ helium atom-molecules thus named atomcules. Apart from their unique dual structure investigated by laser spec-troscopy - a near-circular quasi-classical Rydberg atom with l ∼ n - 1 ∼ 37 or a special diatomic molecule with a negatively charged p̄ nucleus in high rotational state with J = l - the chemical physics aspects of their interaction with other atoms or molecules constitute an interesting topic for molecular physics. While atomcules may resist to million collisions in helium, molecular contaminants such as H2 are likely to destroy them in a single one, down to very low temperatures. In the Born-Oppenheimer framework, we interpret the molecular interaction obtained by ab initio quantum chemical calculations in terms of classical reactive channels, with activation barriers accounting for the experiments carried out in He and H2. From classical trajectory Monte Carlo simulations, we show that the thermalization stage strongly quenches initial populations, thus reduced to a recovered 3 % trapping fraction. This work illustrates the pertinence of chemical physics concepts to the study of exotic processes involving antimatter. New insights into the physico-chemistry of cold interstellar radicals are anticipated.

  • 325. Schwind, Markus
    et al.
    Hosseinpour, Saman
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Johnson, C. Magnus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Langhammer, Christoph
    Zoric, Igor
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Kasemo, Bengt
    Combined in Situ Quartz Crystal Microbalance with Dissipation Monitoring, Indirect Nanoplasmonic Sensing, and Vibrational Sum Frequency Spectroscopic Monitoring of Alkanethiol-Protected Copper Corrosion2013In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 29, no 23, 7151-7161 p.Article in journal (Refereed)
    Abstract [en]

    In this study, we have applied three techniques to simultaneously and in situ study the initial stage of corrosion of copper protected by a self-assembled monolayer of octadecanethiol (ODT). We combined quartz crystal microbalance with dissipation monitoring (QCM-D), indirect nanoplasmonic sensing (INPS), and vibrational sum frequency spectroscopy (VSFS) and obtained complementary information about mass uptake and optical and spectroscopic changes taking place during the initial corrosion phase. All three techniques are very sensitive to the formation of a corrosion film (thickness in the range 0-0.41 nm) under mildly corrosive conditions (dry air, <0.5% relative humidity). The three techniques yield information about the viscoelasticity of the corrosion film (QCM-D), the homogeneity of the corrosion reaction on the surface (INPS), and the stability of the ODT. protection layer (VSFS). Furthermore, by also studying the corrosion process in humid air (ca. 70% relative humidity), we illustrate how the combination of these techniques can be used to differentiate between simultaneously occurring processes, such as water adsorption and corrosion product formation.

  • 326.
    Schütz, Christina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Sort, Jordi
    Bacsik, Zoltan
    Oliynyk, Vitaliy
    Pellicer, Eva
    Fall, Andreas
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Berglund, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Bergström, Lennart
    Salazar-Alvarez, German
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Hard and Transparent Films Formed by Nanocellulose-TiO2 Nanoparticle Hybrids2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 10, e45828- p.Article in journal (Refereed)
    Abstract [en]

    The formation of hybrids of nanofibrillated cellulose and titania nanoparticles in aqueous media has been studied. Their transparency and mechanical behavior have been assessed by spectrophotometry and nanoindentation. The results show that limiting the titania nanoparticle concentration below 16 vol% yields homogeneous hybrids with a very high Young's modulus and hardness, of up to 44 GPa and 3.4 GPa, respectively, and an optical transmittance above 80%. Electron microscopy shows that higher nanoparticle contents result in agglomeration and an inhomogeneous hybrid nanostructure with a concomitant reduction of hardness and optical transmittance. Infrared spectroscopy suggests that the nanostructure of the hybrids is controlled by electrostatic adsorption of the titania nanoparticles on the negatively charged nanocellulose surfaces.

  • 327. Segerie, Audrey
    et al.
    Lin, Li-Li
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Liegeois, Vincent
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Champagne, Benoit
    Effects of the basis set and of the exchange-correlation functional on the Inelastic Electron Tunneling signatures of 1,4-benzenedithiol2014In: Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy, ISSN 1386-1425, E-ISSN 1873-3557, Vol. 119, 34-41 p.Article in journal (Refereed)
    Abstract [en]

    The effects of the atomic basis set and of the exchange-correlation (XC). functional on the Inelastic Electron Tunneling (LET) spectra have been investigated by considering the prototypical 1,4-benzenedithiol molecule. These studies have been completed by tackling the reliability of the same methods for predicting the IR absorption spectrum of the same molecule. The main conclusions are (i) the B3LYP XC functional is suitable to predict the relative vibrational frequencies, (ii) provided a scaling factor is used, the root mean square error on the vibrational frequencies goes down to 18 cm(-1), (iii) triple-zeta basis sets and in particular the cc-pVTZ basis set is a good compromise between accuracy and computational needs, (iv) basis set effects on the IET intensities are larger than those of the XC functional, and (v) the cc-pVTZ, cc-pVQZ, and aug-cc-pVDZ basis sets provide consistent IET intensities.

  • 328. Shi, Changchun
    et al.
    Zhe, Kong
    Sun, Tianyang
    Liang, Lijun
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Zhejiang University, China.
    Shen, Jiawei
    Zhao, Zhengyan
    Wang, Qi
    Kang, Zhengzhong
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Tu, Yaoquan
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Sequence dependence on DNA translocation time by graphene nanoporeManuscript (preprint) (Other academic)
  • 329. Shi, J.
    et al.
    Hedberg, Yolanda
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Lundin, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Karlsson, H. L.
    Möller, L.
    Hemolytic properties of synthetic nano- and porous silica particles: The effect of surface properties and the protection by the plasma corona2012In: Acta Biomaterialia, ISSN 1742-7061, E-ISSN 1878-7568, Vol. 8, no 9, 3478-3490 p.Article in journal (Refereed)
    Abstract [en]

    Novel silica materials incorporating nanotechnology are promising materials for biomedical applications, but their novel properties may also bring unforeseen behavior in biological systems. Micro-size silica is well documented to induce hemolysis, but little is known about the hemolytic activities of nanostructured silica materials. In this study, the hemolytic properties of synthetic amorphous silica nanoparticles with primary sizes of 7-14 nm (hydrophilic vs. hydrophobic), 5-15 nm, 20 nm and 50 nm, and model meso/macroporous silica particles with pore diameters of 40 nm and 170 nm are investigated. A crystalline silica sample (0.5-10 ÎŒm) is included for benchmarking purposes. Special emphasis is given to investigations of how the temperature and solution complexity (solvent, plasma), as well as the physicochemical properties (such as size, surface charge, hydrophobicity and other surface properties), link to the hemolytic activities of these particles. Results suggests the potential importance of small size and large external surface area, as well as surface charge/structure, in the hemolysis of silica particles. Furthermore, a significant correlation is observed between the hemolytic profile of red blood cells and the cytotoxicity profile of human promyelocytic leukemia cells (HL-60) induced by nano- and porous silica particles, suggesting a potential universal mechanism of action. Importantly, the results generated suggest that the protective effect of plasma towards silica nanoparticle-induced hemolysis as well as cytotoxicity is primarily due to the protein/lipid layer shielding the silica particle surface. These results will assist the rational design of hemocompatible silica particles for biomedical applications.

  • 330.
    Shovskyy, Oleksandr
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Varga, Imre
    YKI, Institute of Surface Chemistry.
    Makuska, Ricardas
    Dept of Polymer Chemistry, Vilnius University, Lithania.
    Claesson, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Formation and Stability of Water-Soluble Molecular Polyelectrolyte Complexes: Effects of Charge Density, Mixing Ratio and Polyelectrolyte Concentration2009In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 25, no 11, 6113-6121 p.Article in journal (Refereed)
    Abstract [en]

    The formation of complexes with stoichiometric (1:1) as well as nonstoichiometric (2:1) and (1:2) compositions between oppositely charged synthetic polyelectrolytes carrying strong ionic groups and significantly different molecular weights is reported in this contribution. Poly(sodium styrenesulfonate) (NaPSS) was used as polyanion, and a range of copolymers with various molar ratios of the poly(methacryloxyethyltrimethylammonium) chloride, poly(METAC), and the nonionic poly(ethylene oxide) ether methacrylate, poly(PEO45MEMA), were used as polycations. Formation and stability of PECs have been investigated by dynamic and static light scattering (LS), turbidity, and electrophoretic mobility measurements as a function of polyelectrolyte solution concentration, charge density of the cationic polyelectrolyte, and mixing ratio. The data obtained demonstrate that in the absence of PEO45 side chains the 100% charged polymer (polyMETAC) formed insoluble PECs with PSS that precipitate from solution when exact stoichiometry is achieved. In nonstoichiometric complexes (1:2) and (2:1) large colloidally stable aggregates were formed. The presence of even a relatively small amount of PEO45 side chains (25%) in the cationic copolymer was sufficient for preventing precipitation of the formed stoichiometric and nonstoichiometric complexes. These PEC’s are sterically stabilized by the PEO45 chains. By further increasing the PEO45 side-chain content (50 and 75%) of the cationic copolymer, small, water-soluble molecular complexes could be formed. The data suggest that PSS molecules and the charged backbone of the cationic brush form a compact core, and with sufficiently high PEO45 chain density (above 25%) molecular complexes are formed that are stable over prolonged times.

  • 331.
    Sjöstedt, Anna
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Larsson, Per Tomas
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Innventia AB, Sweden.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Structural changes during swelling of highly charged cellulose fibres2014In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 247, 45-CELL- p.Article in journal (Other academic)
  • 332.
    Skedung, Lisa
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Tactile Perception: Role of Friction and Texture2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Tactile perception is considered an important contributor to the overall consumer experience of a product. However, what physical properties that create the specifics of tactile perception, are still not completely understood. This thesis has researched how many dimensions that are required to differentiate the surfaces perceptually, and then tried to explain these dimensions in terms of physical properties, by interconnecting human perception measurements with various physical measurements. The tactile perception was assessed by multidimensional scaling or magnitude estimation, in which methods human participants assign numbers to how similar pairs of surfaces are perceived or to the relative quantity of a specified perceptual attribute, such as softness, smoothness, coarseness and coolness. The role of friction and surface texture in tactile perception was investigated in particular detail, because typically tactile exploration involves moving (at least) one finger over a textured surface. A tactile approach for measuring friction was developed by means of moving a finger over the surfaces, mounted on a force sensor. The contribution of finger friction to tactile perception was investigated for surfaces of printing papers and tissue papers, as well as for model surfaces with controlled topography. The overarching research goal of this thesis was to study, systematically, the role of texture in tactile perception of surfaces.

    The model surfaces displayed a sinusoidal texture with a characteristic wavelength and amplitude, fabricated by surface wrinkling and replica molding techniques. A library of surfaces was manufactured, ranging in wavelengths from 270 nm up to 100 µm and in amplitudes from 7 nm up to 6 µm. These surfaces were rigid and cleanable and could therefore be reused among the participants. To my knowledge, this is the first time in a psychophysical experiment, that the surface texture has been controlled over several orders of magnitude in length scale, without simultaneously changing other material properties of the stimuli.

    The finger friction coefficient was found to decrease with increasing aspect ratio (amplitude/wavelength) of the model surfaces and also with increasing average surface roughness of the printing papers. Analytical modeling of the finger’s interaction with the model surfaces shows how the friction coefficient increases with the real contact area, and that the friction mechanism is the same on both the nanoscale and microscale. The same interaction mechanism also explains the friction characteristics of tissue paper. Furthermore, it was found that the perceptions of smoothness, coarseness, coolness and dryness are satisfactorily related to the real contact area at the finger-surface interface. 

    It is shown that it is possible to discern perceptually among both printing papers and tissue papers, and this differentiation is based on either two or three underlying dimensions. Rough/smooth and thin/thick were the two main dimensions of surface feel found for the printing papers, whereas friction and wavelength were strongly related to the perceptual cues employed in scaling the model surfaces. These experimental results support the duplex theory of texture perception, which holds that both a “spatial sense”; used to discriminate the roughest textures from the others, and a “vibration sense”; used to discriminate among the smoother textures, are involved. The perception of what is considered rough and smooth depends on the experimental stimulus context. It is concluded that friction is important for human differentiation of surface textures below about 10 µm in surface roughness, and for larger surface textures, friction is less important or can even be neglected.

    The finger friction experiments also allowed the following conclusions to be drawn: (i) The interindividual variation in friction coefficients is too large to allow direct comparison; however, the trends in relative friction coefficients for a group of participants are the same. (ii) Lipids are transferred to the test surface of study, and this lowers the friction. (iii) Many of the studies point to a characteristic frequency during sliding of about 30 Hz, which is both characteristic of the resonance frequency of skin and the expected frequency associated with the fingerprints. (iv) The applied load in surface interrogation is in fact regulated in response to the friction force.

    The limits in tactile perception were indirectly researched by similarity scaling experiments on the model surfaces. Wrinkle wavelengths of 760 nm and 870 nm could be discriminated from untextured reference surfaces, whereas 270 nm could not. The amplitude of the wrinkles so discriminated was approximately 10 nm, suggesting that nanotechnology may well have a role to play in haptics and tactile perception.

  • 333.
    Skedung, Lisa
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Duvefelt, Kenneth
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Young, Jun Chung
    Polymers Division, National Institute of Standards and Technology.
    Stafford, Christopher M.
    Polymers Division, National Institute of Standards and Technology.
    Rutland, Mark
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Tactile friction of controlled fine surface textures: Role of real contact area and adhesionManuscript (preprint) (Other academic)
  • 334.
    Skoglund, Sara
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Lowe, Troy A.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Hedberg, Jonas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Blomberg, Eva
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Wold, Susanna
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Lundin, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Effect of Laundry Surfactants on Surface Charge and Colloidal Stability of Silver Nanoparticles2013In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 29, no 28, 8882-8891 p.Article in journal (Refereed)
    Abstract [en]

    The stability of silver nanoparticles (Ag NPs) potentially released from clothing during a laundry cycle and their interactions with laundry-relevant surfactants [anionic (LAS), cationic (DTAC), and nonionic (Berol)] have been investigated. Surface interactions between Ag NPs and surfactants influence their speciation and stability. In the absence of surfactants as well as in the presence of LAS, the negatively charged Ag NPs were stable in solution for more than 1 day. At low DTAC concentrations (<= 1 mM), DTAC-Ag NP interactions resulted in charge neutralization and formation of agglomerates. The surface charge of the particles became positive at higher concentrations due to a bilayer type formation of DTAC that prevents from agglomeration due to repulsive electrostatic forces between the positively charged colloids. The adsorption of Berol was enhanced when above its critical micelle concentration (cmc). This resulted in a surface charge dose to zero and subsequent agglomeration. Extended DLVO theory calculations were in compliance with observed findings. The stability of the Ag NPs was shown to depend on the charge and concentration of the adsorbed surfactants. Such knowledge is important as it may influence the subsequent transport of Ag NPs through different chemical transients and thus their potential bioavailability and toxicity.

  • 335.
    Song, Brian Xiaoqing
    et al.
    Procter & Gamble Company.
    Berger, Patricia Sara
    Procter & Gamble Company.
    Schwartz, James Robert
    Procter & Gamble Company.
    Corkery, Robert W.
    Procter & Gamble Company.
    Complete-cycle methods for protecting glassware from surface corrosion in automatic dishwashing appliances2007Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    Complete-cycle methods for protecting glassware from corrosion in automatic dishwashing appliances use a through-the-wash detergent compn., esp. detergent compns. comprising zinc-contg. materials, in combination with a rinse aid compn., esp. rinse aid compns. comprising at least one water-sol. metal salt. Such a domestic, institutional, industrial, and/or com. complete-cycle method of treating glassware surfaces in automatic dishwashing comprises the steps of: (a) providing a through-the-wash detergent compn. comprising an effective amt. of a particulate zinc-contg. material; (b) providing a rinse aid compn. comprising an effective amt. of at least one metal salt; (c) contacting said glassware surface with said through-the-wash detergent compn.; and (d) contacting said glassware surface with said rinse aid compn. in the rinse cycle. [on SciFinder(R)]

  • 336.
    Song, Brian Xiaoqing
    et al.
    Procter & Gamble Company.
    Berger, Patricia Sara
    Procter & Gamble Company.
    Schwartz, James Robert
    Procter & Gamble Company.
    Corkery, Robert W.
    Procter & Gamble Company.
    Complete-cycle methods for protecting glassware from surface corrosion in automatic dishwashing appliances2003Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    Detergent compns. comprising zinc-contg. materials, are used to protect glassware from surface corrosion during automatic dishwashing. A domestic, institutional, industrial, and/or com. through-the-wash method of treating glassware in automatic dishwashing process, comprises the step of contacting a glassware surface with a through-the-wash automatic dishwashing detergent compn. comprising: (a) an effective amt. of a zinc-contg. layered material; (b) a detergent active; (c) optionally, one or more of the following: a dispersant polymer or carrier medium; and (d) optionally, an adjunct ingredient. [on SciFinder(R)]

  • 337.
    Song, Brian Xiaoqing
    et al.
    Procter & Gamble Company.
    Berger, Patricia Sara
    Procter & Gamble Company.
    Schwartz, James Robert
    Procter & Gamble Company.
    Corkery, Robert W.
    Procter & Gamble Company.
    Compositions for protecting glassware from surface corrosion in automatic dishwashing appliances2003Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    Through-the-wash automatic dishwashing detergent compns., esp. detergent compns. comprising zinc-contg. materials, are used to protect glassware from surface corrosion during automatic dishwashing. Such a domestic, institutional, industrial, and/or com. through-the-wash automatic dishwashing detergent compn. comprises: (a) an effective amt. of a zinc-contg. layered material; (b) a detergent active; (c) optionally, one or more of the following: a dispersant polymer or carrier medium; and (d) optionally, an adjunct ingredient. [on SciFinder(R)]

  • 338.
    Song, Brian Xiaoqing
    et al.
    Procter & Gamble Company.
    Berger, Patricia Sara
    Procter & Gamble Company.
    Schwartz, James Robert
    Procter & Gamble Company.
    Corkery, Robert W.
    Procter & Gamble Company.
    Methods for treating glassware surfaces using zinc-containing corrosion protection agents.2003Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    A treatment system corrosion protection agents, esp. corrosion protection agents comprising zinc-contg. materials, is used for treating glassware for example dishes and glasses, with reduced surface corrosion. Such a domestic, institutional, industrial, and/or com. method of reducing glassware surface corrosion in an automatic dishwashing appliance comprises the step of contacting a glassware surface with a corrosion protection agent comprising: (a) an effective amt. of a zinc-contg. layered material; and (b) optionally, an adjunct ingredient. [on SciFinder(R)]

  • 339.
    Soroka, Inna L.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Tarakina, Nadezda V.
    Korzhavyi, Pavel A.
    Stepanenko, Vladimir
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Effect of synthesis temperature on the morphology and stability of copper(I) hydride nanoparticles2013In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 15, no 42, 8450-8460 p.Article in journal (Refereed)
    Abstract [en]

    The effect of synthesis temperature on the morphology and stability of copper(I) hydride nanoparticles is studied. Monovalent copper hydride is obtained by reduction of Cu2+ sulfate with hypophosphorous acid at temperatures ranging from 45 degrees C to 75 degrees C. The CuH nanoparticles that formed have the shape of desert roses and are found to be very porous. The lattice parameter, size, and morphology of these nanoparticles depend on the synthesis temperature. CuH is a metastable compound. In air under ambient conditions, it first decomposes into copper metal and hydrogen gas and then the copper oxidizes. The copper particles that are left after the decomposition of copper(I) hydride in air have the same desert-rose morphology as the CuH nanoparticles. The copper particles with desert-rose shapes are observed for the first time. Copper(I) hydride decomposes slower in an aqueous environment than in air to form copper(I) oxide as the final product through formation of hydrated copper(I) hydroxide as an intermediate phase. The retarded decomposition of CuH in water may be explained by the formation of a protective CuOH center dot H2O layer on the surface of copper(I) hydride.

  • 340.
    Springer, Valeria
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Jacksén, Johan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Ek, Patrik
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Lista, Adriana G.
    Emmer, Åsa
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Determination of fluoroquinolones in bovine milk samples using a pipette-tip SPE step based on multiwalled carbon nanotubes prior to CE separation2014In: Journal of Separation Science, ISSN 1615-9306, E-ISSN 1615-9314, Vol. 37, no 1-2, 158-164 p.Article in journal (Refereed)
    Abstract [en]

    A simple CE-UV method was developed for the simultaneous determination of ciprofloxacin, norfloxacin, and ofloxacin in milk samples. The optimum separation was obtained using a 20 mM ammonium dihydrogenphosphate solution with 2 mM cetyltrimethylammonium bromide at pH 3.0 as the BGE. Satisfactory resolution for structurally very similar analytes, like norfloxacin and ciprofloxacin, was achieved without including any organic solvent. Milk samples were prepared using a simple/extraction procedure based on acidic protein precipitation followed by an SPE step using only 5 mg of multiwalled carbon nanotubes as the sorbent material. The LODs for the three compounds were between 7.5 and 11.6 g/L and the RSDs for the peak areas were between 2.6 and 4.9%. The complete method was applied to spiked real milk samples with satisfactory recoveries for all analytes (84-106%).

  • 341.
    Sterner, M.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Multicomponent fractionation of Saccharina latissima brown algae using chelating salt solutions2016In: Journal of Applied Phycology, ISSN 0921-8971, E-ISSN 1573-5176, 1-14 p.Article in journal (Refereed)
    Abstract [en]

    A fractionation strategy for Saccharina latissima algal biomass was developed utilizing chelating extraction salt solutions to mediate the liberation of algal components. Alginate, cellulose, laminarin, mannitol, protein, and inorganic salts were quantified in the fractions to reveal their individual dissolution patterns. Chelation power was identified as a key parameter for liberating alginate and increasing the yield of extracted components. The most efficient fractionation was achieved using aqueous sodium citrate as the extraction solution, producing an alginate-rich soluble fraction and a salt-poor insoluble fraction rich in cellulose and protein. Extractions at decreased pH were shown to be beneficial because they decreased the M/G ratio of the extracted alginate and concentrated the protein in the insoluble fraction from which it can easily be recovered; these effects could be achieved by switching the traditional sodium carbonate extraction solution with salts that have chelation capacity at lower pH. A cyclic extraction demonstrated that the sodium citrate solution can be reused for multiple alginate extractions with the buildup of the concentrations of other valuable components in the solution.

  • 342.
    Stockmann-Juvala, H.
    et al.
    Finnish Institute of Occupational Health, Risk assessment and biomonitoring, Helsinki, Finland.
    Zitting, A.
    Finnish Institute of Occupational Health, Risk assessment and biomonitoring, Helsinki, Finland.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Darrie, G.
    International Chromium Development association, Paris, France.
    Santonen, T.
    Finnish Institute of Occupational Health, Risk assessment and biomonitoring, Helsinki, Finland.
    Use of read-Across in the health risk assessment of ferrochromium alloys under reach2010In: Proceedings of the 12th International Ferroalloys Congress: Sustainable Future, 2010, 35-42 p.Conference paper (Refereed)
    Abstract [en]

    In REACH regulation there is a category of substances called special preparations, to which alloys belong. In the assessment of special preparations not only the bulk composition of an alloy, but also the way the constituent metals are bonded in the chemical matrix, shall be taken into account. The surface of the alloy may limit the ability of constituent metals to be released from the matrix and thus affect the toxicological profile of an alloy. Therefore, the surface characteristics and the release rates of metals shall be taken into account. Finnish Institute of Occupational Health has been carrying out REACH-compliant chemical safety assessment of ferrochromium in collaboration with International Chromium Development Association. Ferrochromium is composed mainly of chromium and iron with small amounts of other metals, e.g. nickel. Since almost no studies have been published on the health effects of ferrochromium, the assessment of ferrochromium should be based on its constituent metals. An approach used in this study included the use of data on surface composition and release of metal constituents from ferrochromium. The chromium oxide surface layer limits the release of nickel and other constituents from ferrochromium and affects the toxicological profile. As a result it can be concluded that ferrochromium alloys can be likened to chromium metal and stainless steel when assessing their health hazards. Thus, the risk assessment can be based largely on existing human, animal and in vitro toxicity data on chromium metal, chromium(III)oxide and stainless steel. By referring to this data, it was possible to make conclusions on health hazards of ferrochromium without need to carry out any new toxicity tests.

  • 343. Stockmann-Juvala, Helene
    et al.
    Zitting, Antti
    Darrie, Grant
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Santonen, Tiina
    Read-across approach in the risk assessment of ferrochromium. Case: Repeated dose toxicity2009In: Toxicology Letters, ISSN 0378-4274, E-ISSN 1879-3169, Vol. 189, S245-S245 p.Article in journal (Refereed)
  • 344. Stokes, Francesca A.
    et al.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Harford, Philip J.
    Peel, Andrew J.
    Less, Robert J.
    Wheatley, Andrew E. H.
    Wright, Dominic S.
    Towards the Synthesis of Guanidinate- and Amidinate-Bridged Dimers of Mn and Ni2014In: Australian journal of chemistry (Print), ISSN 0004-9425, E-ISSN 1445-0038, Vol. 67, no 7, 1081-1087 p.Article in journal (Refereed)
    Abstract [en]

    Reactions of Cp2M (Cp = cyclopentadienyl, M = Mn, Ni) with lithium amidinates and guanidinates are reported. The highly oxophilic nature of Mn leads to the isolation of the interstitial oxide Mn4O(MeN - CH - NMe)(6) (4) in preference to the intended paddle-wheel homodimer Mn-2(MeN - CH - NMe)(4) when employing the sterically uncongested amidinate [MeN - CH - NMe](-) ligand. In contrast, an analogous reaction using Cp2Ni yielded Ni-2(MeN - CH - NMe)(4) (5). The use of monoprotic guanidinate ligands also gave contrasting results for Mn and Ni. In the first case, the highly unusual spirocycle Mn{mu-NC(NMe2)(2)}(4)Li-2 center dot 3THF (6) was produced in low yield. For M = Ni, use of the [hpp](-) (1,3,4,6,7,8hexahydro-2H-pyrimido[1,2-alpha] pyrimidinate) ligand gives results comparable with the synthesis of 5, with Ni-2(hpp) 4 (7) isolated. In contrast to recent data obtained using Cp2Cr, the guanidinate ligands do not sequester coformed CpLi. Density functional theory analysis corroborates the view that the intermetal distance in each of the reported dinickel paddle-wheel complexes (2.4846(8) and 2.3753(5) angstrom in 5 and 7 respectively) is defined by the geometric parameters of the bidentate ligands and that intermetal bonding is not present.

  • 345.
    Sun, Xianqiang
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Tu, Yaoquan
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Computational investigation of G-proteins releasing from G-protein-coupled receptors2013In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 246, 193-POLY- p.Article in journal (Other academic)
  • 346.
    Sun, Yang
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Olsén, Peter
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Waag, Thilo
    Krueger, Anke
    Steinmüller-Nethl, Doris
    Albertsson, Ann-Chrisine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Finne-Wistrand, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Disaggregation and Anionic Activation of Nanodiamonds Mediated by Sodium Hydride: A New Route to Functional Aliphatic Polyester-Based Nanodiamond Materials2014In: Particle & particle systems characterization, ISSN 0934-0866, E-ISSN 1521-4117, Vol. 32, no 1, 35-42 p.Article in journal (Refereed)
    Abstract [en]

    Polylactide-modified nanodiamond particles (n-DP-g-PLA) are prepared by sodium-hydride-activated nanodiamond-initated anionic ring-opening polymerization. Activated nanodiamond particles repel each other, preventing agglomeration during the polymerization. This universal modification provides a platform for the functionalization of all types of nanoparticles containing hydroxyl groups.

  • 347. Svagan, A.J.
    et al.
    Bender Koch, C.
    Hedenqvist, Mikael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Nilsson, Fritjof
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Glasser, G.
    Baluschev, S.
    Andersen, M.L.
    Liquid-core nanocellulose-shell capsules with tunable oxygen permeability2016In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 136, 292-299 p.Article in journal (Refereed)
    Abstract [en]

    Encapsulation of oxygen sensitive components is important in several areas, including those in the food and pharmaceutical sectors, in order to improve shelf-life (oxidation resistance). Neat nanocellulose films demonstrate outstanding oxygen barrier properties, and thus nanocellulose-based capsules are interesting from the perspective of enhanced protection from oxygen. Herein, two types of nanocellulose-based capsules with liquid hexadecane cores were successfully prepared; a primary nanocellulose polyurea-urethane capsule (diameter: 1.66 μm) and a bigger aggregate capsule (diameter: 8.3 μm) containing several primary capsules in a nanocellulose matrix. To quantify oxygen permeation through the capsule walls, an oxygen-sensitive spin probe was dissolved within the liquid hexadecane core, allowing non-invasive measurements (spin-probe oximetry, electron spin resonance, ESR) of the oxygen concentration within the core. It was observed that the oxygen uptake rate was significantly reduced for both capsule types compared to a neat hexadecane solution containing the spin-probe, i.e. the slope of the non-steady state part of the ESR-curve was approximately one-third and one-ninth for the primary nanocellulose capsule and aggregated capsule, respectively, compared to that for the hexadecane sample. The transport of oxygen was modeled mathematically and by fitting to the experimental data, the oxygen diffusion coefficients of the capsule wall was determined. These values were, however, lower than expected and one plausible reason for this was that the ESR-technique underestimate the true oxygen uptake rate in the present systems at non-steady conditions, when the overall diffusion of oxygen was very slow.

  • 348.
    Svärd, Michael
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Nordström, Fredrik L.
    Hoffmann, Eva-Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Aziz, Baroz
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Rasmuson, Åke C.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena. Department of Chemical and Environmental Science, Solid State Pharmaceutical Cluster, Materials and Surface Science Institute, University of Limerick, Ireland .
    Thermodynamics and nucleation of the enantiotropic compound p-aminobenzoic acid2013In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 15, no 25, 5020-5031 p.Article in journal (Refereed)
    Abstract [en]

    In this work, the thermodynamic interrelationship of the two known polymorphs of p-aminobenzoic acid has been explored, and primary nucleation in different organic solvents investigated. The solubility of both polymorphs in several solvents at different temperatures has been determined and the isobaric solid-state heat capacities have been measured by DSC. The transition temperature below which form α is metastable is estimated to be 16°C by interpolation of solubility data and the melting temperature of form β is estimated to be 140°C by extrapolation of solubility data. Using experimental calorimetry and solubility data the thermodynamic stability relationship between the two polymorphs has been estimated at room temperature to the melting point. At the transition temperature, the estimated enthalpy difference between the polymorphs is 2.84 kJ mol-1 and the entropy difference is 9.80 J mol-1 K-1. At the estimated melting point of form β the difference in Gibbs free energy and enthalpy is 1.6 kJ mol-1 and 5.0 kJ mol-1, respectively. It is found that the entropic contribution to the free energy difference is relatively high, which explains the unusually low transition temperature. A total of 330 nucleation experiments have been performed, with constant cooling rate in three different solvents and with different saturation temperatures, and multiple experiments have been carried out for each set of conditions in order to obtain statistically significant results. All performed experiments resulted in the crystallization of the high-temperature stable α-polymorph, which is kinetically favoured under all evaluated experimental conditions. The thermodynamic driving force required for nucleation is found to depend chiefly on the solvent, and to be inversely correlated to both solvent polarity and to solubility.

  • 349.
    Swerin, Agne
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Mira, I.
    Ink-jettable paper-based sensor for charged macromolecules and surfactants2014In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 195, 389-395 p.Article in journal (Refereed)
    Abstract [en]

    The use of metachromatic dye-based formulations for the preparation of inkjettable prototype indicators suitable for the detection of charged macromolecules, surfactants or other low molecular weight molecules was investigated. Such indicators were based on the use of metachromatic o-toluidine blue (OTB) that undergoes a characteristic change in color (from blue to pink) upon interaction with anionic macromolecules. When applied onto absorbing substrates such as paper and paperboard, solutions containing OTB and the same dye in the presence of potassium polyvinyl sulfate (KPVS), proved to indicate negatively charged polymers and cationic surfactants. The colorimetric responses suggest a detection limit and sensitivity both are in the order of 1 mM of charged species but can be further improved. Interactions between active species in the indicators and some of the additives in inkjettable formulations (surfactant and humectants) interfered with the mechanism by which an OTB/KVPS-based system work only to a minor degree and could be overcome by priming the substrate. An OTB-based system was formulated into an inkjettable formulation that, once applied to a substrate, was showed to indicate charged polymers and surfactants. This concept has the potential for sensing/indication of other charged macromolecules, such as carboxylates and polyphosphates, which are relevant in biomedical (e.g. fouling due to microbial activity), packaging applications (e.g. migration or release of compounds, food spoilage), microfluidic devices or a simple dipstick application to indicate the presence of charged components.

  • 350.
    Sörensen, M. H.
    et al.
    YKI, Institute for Surface Chemistry.
    Samoshina, Yulia
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Per, Claesson
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Alberius, Peter
    YKI, Institute for Surface Chemistry.
    Sustained Release of Ibuprofen from Polyelectrolyte Encapsulated Mesoporous Carriers2009In: Journal of Dispersion Science and Technology, ISSN 0193-2691, E-ISSN 1532-2351, Vol. 30, no 6, 892-902 p.Article in journal (Refereed)
    Abstract [en]

    Polyelectrolyte multilayers are receiving much attention due to their insoly. and due to structural responses induced in them by changes in soln. properties such as, for example, temp., pH or ionic strength.  These characteristics make polyelectrolyte multilayers highly interesting in encapsulation technol. and controlled delivery applications.  However, producing dry, biocompatible formulations for storage of low mol. wt. substances poses a challenge.  One possibility is to make use of a well-defined mesoporous inorg. carrier material as host for the model substance (in the authors' case ibuprofen).  Control over release properties are enabled by polyelectrolyte encapsulation of the inorg. carrier.  The authors built such multilayers through consecutive deposition of PAH and PSS on top of a first layer of PEI.  These layers were adsorbed either in presence or absent of ibuprofen.  The influence of long time storage, 2 years, of the samples was also investigated.  The polyelectrolyte multilayer structure was investigated in detail by Dual Polarization Interferometry (DPI), and the authors use these data to interpret the measured release profiles.

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