EFFECT OF SPACER LENGTH ON THE PHASE-TRANSITION OF POLYMER LMWLC COMPOSITES/

Low molecular weight liquid crystals (LMWLCs), 4-[(4-bromoalkyloxy)-ph enylazo]benzonilrile (AZO(n)) series were synthesized. Mesogenic monom ers, 4-(4-propenoylalkyloxy)-4'-cyanobiphenyl (MCA) were synthesized a nd both homopolymer and copolymer with a methyl methacrylate (MMA) uni t were prepared by free radical polymerization. Polymer/LMWLC composit es (P/LCs) were prepared with LMWLC AZO(6) and AZO(8) and non-mesomorp hic SCLCPs, PMCA(6)-3 and PMCA(8)-3, where (6) and (8) represent the n umber of methylene unit in the spacers of both LMWLC and SCLCP. It was observed that Delta T-g (defined as T-g of polymer-T-g of P/LC) was s maller and Delta T-NI (defined as T-NI of LMWLC-T-NI of P/LC) was larg er, respectively in the case of P/LC samples with the same (6/6 and 8/ 8) spacer length.