Thermotropic perfluoroalkyl azobenzoates. Studies of low molar mass compounds and side chain polymer derivatives

Bao, Xujin and Dix, Leslie (1999) Thermotropic perfluoroalkyl azobenzoates. Studies of low molar mass compounds and side chain polymer derivatives. Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals, 333 (1). pp. 25-33. ISSN 1058-725X

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Abstract

A series of 4′-[(carbonyloxy-1,1,2,2 Tetrahydrofluorodecyl)]-4 -(ω-bromo-alkenyloxy) azobenzenes, 4′-[(carbonyloxy-1,1,2,2-Tetrahydrofluorodecyl)]-4-(alk-1-enyloxy) azobenzenes have been synthesized. Also, a polyacrylate has been formed by phase transfer catalyzed reaction between one of the ω-bromo-alkenyloxy compounds and sodium polyacrylate as well as two polysiloxanes formed by hydrosilylation of the alkenyloxy compounds and a polyhydrosilane. All of the low molar mass compounds show the S A phase on heating and an increase in perfluoroalkyl chain length results in an increase in clearing temperature whilst an increase in the hydrocarbon chain length shows a decrease in clearing temperature. Upon grafting these low molar mass units to a polymer backbone, the resulting materials also show smectic mesophases despite having quite low clearing entropies (ΔS/R to approximately 0.2-0.6). The precursor polymers are of low molar mass (Mw 1200-1800 g mol -1) and this may be the reason why the polymers do not show glass transition temperatures.

Item Type:	Article
Uncontrolled Keywords:	perfluoroalkylated liquid crystals, thermotropic Azobenzene compounds, side chain liquid crystal polymers
Department:	Faculties > Health and Life Sciences > Applied Sciences
Depositing User:	Becky Skoyles
Date Deposited:	16 Feb 2015 11:24
Last Modified:	12 Oct 2019 17:29
URI:	http://nrl.northumbria.ac.uk/id/eprint/19127

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