Abstract
For a spacer structure in a side group liquid crystalline polyacrylate, we have reported that a segmented spacers, which consisted of oligo(ethylene oxide) and alkyl segments, promoted the mobility of a mesogen and decreased the glass transition temperature, Tg, compared with an ordinary alkylene spacer. In this work, two series of polyacrylates, xEO-Cy and Cp-qEO, were prepared to study the influence of the length and the linking-order of these segments on the thermal properties. As a result, almost xEO-Cys, which had mesogens connected to alkylene segments, exhibited LC phases while all Cp-qEOs, which had mesogens connected to oligo(ethylene oxide), had no mesophases. In the case of xEO-Cys, longer alkylene chains (y=10,11) in the segmented spacers induced crystalline phases, and for cases below y=9 a decrease of an alkylene length depressed the ranges of the LC phases. In addition, the increase of segment length of an oligo(ethylene oxide) contracted the range of the LC phase. Consequently, it was found that the hydrophilic domain, which consisted of polymer-backbone and oligo(ethylene oxide), and hydrophobic domain, which consisted of alkylene chains and mesogens, assembled each other and improved the order of mesogens, and that appropriate composition of these segments was necessary to give wide range LC phase to the polymer.
