Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 354677
Title Banana-shaped side chain liquid crystalline siloxanes
Author(s) Achten, R.; Koudijs, A.; Giesbers, M.; Reddy, R.A.; Verhulst, T.; Tschierske, C.; Marcelis, A.T.M.; Sudhölter, E.J.R.
Source Liquid Crystals 33 (2006)6. - ISSN 0267-8292 - p. 681 - 688.
Department(s) Organic Chemistry
Publication type Refereed Article in a scientific journal
Publication year 2006
Keyword(s) bent-core mesogens - mesomorphic properties - achiral molecules - polar order - chirality - phases - units - polymers - design - field
Abstract Eight banana-shaped side chain liquid crystalline oligomers and polymers have been synthesized by hydrosilylation of vinyl-terminated bent-core mesogens with trimethylsilyl-terminated siloxanes. The synthesized oligomers and polymers, and their olefinic precursors, were investigated by polarizing optical microscopy (POM), differential scanning calorimetry, X-ray diffraction (XRD), electro-optical experiments and Maldi-Tof. The short-tailed olefins form a Colr mesophase, whereas those with longer chains exhibit the SmCPA mesophase. All the oligomers and polymers studied show liquid crystalline properties and do not crystallize upon cooling. Most oligomers with around four repeating siloxane units, show a lamellar (layer) structure and antiferroelectric switching properties, the SmCPA phase. XRD shows that the layer spacings are hardly influenced by the length of the terminal tails. The oligomer prepared from the smallest olefinic precursor, having the shortest alkyl tail, shows an XRD pattern reminiscent of a columnar phase, although POM displays domains of opposite chirality, and no switching behaviour could be detected. The polymers with around 35 repeating siloxane units are liquid crystalline, but due to their high viscosity a thorough characterization of the liquid crystalline phases was impossible
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