Convenient synthesis of a discotic side group liquid crystal polymer

Abstract

The synthesis of a discotic side group liquid crystal polymer based on poly(methyl methacrylate) is reported. This involves the oxidative coupling of 3,3′,4,4′-tetrakis(hexyloxy)biphenyl with 1-hexyloxy-2-methoxybenzene to yield the unsymmetrical triphenylene nucleus, 2-methoxy-3,6,7,10,11-pentakis(hexyloxy)triphenylene. Subsequent demethylation followed by reactions first with 1,11-dibromoundecane and then with the potassium salt of methacrylic acid yielded the polymerisable monomer, 11-[3,6,7,10,11-pentakis(hexyloxy)-2-oxytriphenylene]undecyl methacrylate. This was polymerised in benzene using azoisobutyronitrile as the initiator. The thermal properties of the resulting polymer are described.