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Tailoring Phospholes for Imprint of Fluorescent 3D Structures
(2019-11-06)
PMMA based polymer blends have been infused with luminescent phospholes and have been structured via nanoimprint. While symmetrically substituted phospholes are prone to crystallization and phase separation, structural modification of the phosphole backbone in the α‐ and β‐positions has been explored, which prevents these issues; a structural explanation for this is suggested. Best phase integrity has been obtained for β‐silyl‐substituted phospholes, which were implemented in thin films and beads. The emission ...
Aufsatz
A simulation-based approach to evaluate objective material parameters from concrete rheometer measurements
(2019-12-31)
Modern concretes such as ultra-high performance concrete (UHPC) show excellent strength properties combined with favorable flow properties. However, the flow properties depend strongly on process parameters during production (temperature, humidity etc.), but also change sensitively even with slight variations in the mixture. In order to ensure desired processing of the fluidlike material and consistent process quality, the flow properties of the concrete must be evaluated quantitatively and objectively. The usual ...
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Photoinduced supramolecular chirality and spontaneous surface patterning in high-performance azo materials
(2019-06-18)
In this work, two photo-structuring processes, photo induced spontaneous surface structuring (PSSP) and photo induced supramolecular chirality (PSC) are applied to high-performance azo polymers. We demonstrate higher induced optical rotation than described previously in other reports and show that self-organized surface morphologies are not detrimental for the formation of PSC.
Aufsatz
Generation of twisted nanowires with achiral organic amphiphilic copper complexes
(2019-01-14)
Drying under solvent atmosphere (DUSA) was investigated as an experimental technique to generate self-assembled nanowires and needles from solutions of organic molecules under controlled conditions. Experimental observations of twisted nanowires are reported. These twisted nanowires were obtained by drying of solutions of achiral molecules under solvent controlled atmospheres: achiral, amphiphilic copper complexes were dissolved in an achiral solvent and these solutions were dried under controlled conditions. Two ...
Aufsatz
Amplified Spontaneous Emission in Paper
(2019-02-12)
Industrially produced copy paper is presented as a novel optical material for narrow-band stimulated emission. Fluorescent brightening agents (FBA) such as Calcofluor White provide enough gain to exceed the threshold for amplified spontaneous emission. By applying an additional dye such as Coumarin 307, or simply a highlighter pen, the emission line can be shifted from blue (~440 nm), towards turquoise (>480 nm), up to orange (590 nm) which can be useful for spectroscopic applications. These properties are demonstrated ...
Aufsatz
Bis‐[3]Ferrocenophanes with Central >E−E’< Bonds (E, E’=P, SiH): Preparation, Properties, and Thermal Activation
(2019-06-26)
A series of bis‐[3]ferrocenophanes of the general type Fe(C5H4E’)2E−E(E'C5H4)2Fe (E=P, SiH and E’=PtBu, NneoPentyl, NSi(CH3)3) with an isolobal molecular framework have been prepared and characterized by heteronuclear NMR spectroscopy and X‐ray crystallography. The thermal dissociation behavior with respect to homolytic fission of the central bond generating phosphorus centered radicals was investigated using EPR spectroscopy and quantum chemical calculations.