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

Xujin Bao, Leslie Dix

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

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.
Original languageEnglish
Pages (from-to)25-33
JournalMolecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals
Volume333
Issue number1
DOIs
Publication statusPublished - 1999

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