Chemphyschem. 2011 Dec 23;12(18):3591-603. doi: 10.1002/cphc.201100301. Epub 2011 Nov 03.

Self-assembly of linear and cyclic siloxane-containing mesogens: investigation of layered structures in bulk and thin films.

Chemphyschem : a European journal of chemical physics and physical chemistry

Paul Heinz, Konrad Hindelang, Anastasia Golosova, Christine M Papadakis, Bernhard Rieger

PMID: 22052820 DOI: 10.1002/cphc.201100301

Abstract

Silicon-containing materials which possess the ability to form mesophases are promising systems for applications in the fields of electro-optical devices, nonlinear optics, and information storage media. In this work, the formation of supramolecular assemblies of a series of low molecular weight siloxane-containing mesogens is presented. Besides a novel synthesis route via Ru(II) -catalyzed hydrosilylation of phenyl acetylene derivatives, mesophase characterization by modern analysis techniques is performed. As linker groups, leading to bi- and tetramesogens, linear disiloxane and cyclic tetrasiloxane are utilized. In the resulting class of materials, high thermal stability, induced by the formation of layered smectic-type structures, is predominant. The smectic-type phases were found to be monotropic. Layer distances in the assemblies, as well as the phase transition temperatures, can be controlled by the substitution motif on the mesogens (number and length of alkyl chains). In spin-cast thin films, the layered domains are visualized by atomic force microscopy; furthermore, domain dimensions and electron densities are determined by grazing-incidence small-angle X-ray scattering.

Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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• Journal Article