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Blanchard N.E.,Empa - Swiss Federal Laboratories for Materials Science and Technology | Blanchard N.E.,ETH Zurich | Naik V.V.,ETH Zurich | Geue T.,Paul Scherrer Institute | And 4 more authors.
Langmuir | Year: 2015

Thin plasma polymer films were deposited in hexamethyldisiloxane (HMDSO) and HMDSO/O2 low-pressure discharges and their chemical structures analyzed using infrared (IR) spectroscopy and neutron reflectometry (NR). The (plasma-polymerized) ppHMDSO film exhibits hydrophobic, poly(dimethylsiloxane)-like properties, while the retention of carbon groups is reduced by O2 addition, yielding a more inorganic, hydrophilic ppSiOx film. Both films show a minor (vertical) density gradient perpendicular to the substrate, where the exposed film surface seems to be more oxidized, indicating oxidative aging reactions upon contact with air. The hydration and water uptake abilities of the films in aqueous environments were investigated in humid environments using ellipsometry, NR in D2O, and multiple transmission-reflection IR measurements after equilibration of the films in water. © 2015 American Chemical Society.

Scholz G.,Humboldt University of Berlin | Krahl T.,BAM Federal Institute of Materials Research and Testing | Ahrens M.,Humboldt University of Berlin | Ahrens M.,Fraunhofer Research Institution for Polymeric Materials and Composites PYCO | And 5 more authors.
Journal of Fluorine Chemistry | Year: 2011

This study presents for the first time an NMR spectroscopic characterization of the room and high temperature phases of (NH 4)3InF6 using 19F and 115In as probe nuclei. The reversible phase transition to the cubic phase at 353 K was followed by MAS NMR in situ. Static NMR experiments of the room temperature phase and MAS NMR experiments of the high temperature phase allowed the determination of the NMR parameters of both nuclei. Finally, the scalar In-F coupling, rarely observed in solid state NMR, is evidenced in both room and high temperature phases of (NH4)3InF6, and measured in the high temperature phase. © 2011 Elsevier B.V. All rights reserved.

Galeotti F.,CNR Institute for Macromolecular Studies | Hartmann L.,Fraunhofer Research Institution for Polymeric Materials and Composites PYCO | Botta C.,CNR Institute for Macromolecular Studies
Journal of Colloid and Interface Science | Year: 2016

We propose a novel fabrication method for realizing robust and solvent resistant honeycomb films by combining parylene deposition with the polymer auto-organization phenomenon leading to breath figures. Parylene CVD process is suitable for producing a conformal protective layer on the honeycomb surface, reinforcing and stabilizing this structure. We demonstrate that the stabilized porous films can be filled with chloroform solution of fluorescent materials, without losing the integrity of their microstructure. In addition, liquid crystals can be encapsulated inside the patterned surface between two layers of parylene, showing interesting organization features dictated by the spatial constrains. This is the first reported application of breath figures with liquid crystals, suggesting a new approach for the development of honeycomb-based liquid crystal cells for flexible displays. © 2015 Elsevier Inc..

Kenfack F.,Fraunhofer Research Institution for Polymeric Materials and Composites PYCO | Bauer M.,Fraunhofer Research Institution for Polymeric Materials and Composites PYCO | Bauer M.,TU Brandenburg
Energy Procedia | Year: 2014

A new Phase Change Material (PCM) based on a salt hydrate which can be incorporated in latent heat storage systems for efficient handling of thermal energy around 100°C has been prepared. Compared with the pure salt hydrate, the results showed that the newly developed salt hydrate PYCO-PCM-1 is of high thermal stability. The storage capacity of 83.33 kWh m-3 for a temperature range ΔT = 20 K, corresponds to about four times the energy which can be stored with the same volume of water. Expanded graphite has been proven as a promising additive for improving the conductivity of PYCO-PCM-1. © 2014 The Authors.

Steffen S.,Fraunhofer Research Institution for Polymeric Materials and Composites PYCO | Bauer M.,Fraunhofer Research Institution for Polymeric Materials and Composites PYCO | Decker D.,Clariant | Richter F.,Clariant
Journal of Applied Polymer Science | Year: 2014

This introduces an organic-inorganic thermosetting hybrid resin system based on unsaturated polyester and polysilazanes. It shows the chemical modification of unsaturated polyester structures by end capping to enable the combination of both components. In general, halogen-free unsaturated polyesters are not fire-retardant and have to be equipped with additives. Fillers and intumescent additives are preponderantly used in today's fire-retardant formulations. In contrast to these fire-retardants, polysilazanes act as ceramizing agents. Polysilazanes are suitable fire-retardants for resin transfer molding due to their low viscosity. Both burning behavior and glass transition temperature (Tg) are investigated as important application properties. In contrast to state-of-the-art fire-retardant formulations polysilazane-based thermosetting hybrid resins burn with high intensity and fast extinction. Therefore, total heat and smoke emission is decreased. The formation of ceramic structures during burning results in high residual mechanical properties and a low mass loss. © 2014 Wiley Periodicals, Inc.

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