Orientational order of a nematic polymer grafted on polytetrafluoroethylene

Abstract

The orientation behavior of a nematic side‐chain polymer grafted on polytetrafluoroethylene (PTFE) is studied. The sandwich‐like composite was prepared by the graft post‐polymerization of 4‐cyan‐4′‐(biphenyloxy)butyl acrylate on a PTFE film pretreated by vacuum ultraviolet irradiation (VUV). The oriented liquid crystal layer was prepared by mechanical stretching of the composite film. Orientation degree was measured by means of FT‐IR spectroscopy. The orientation function increases with the increasing strain and attains the upper limit value at the strain Δl/l > 1.0. The temperature dependence of the orientation degree is completely reversible under cooling and heating. Copyright © 2000 John Wiley & Sons, Ltd.

Selected Issues in Liquid Crystal Elastomers and Gels

“…This method has been used in many studies, although it is a considerably complicated and delicate two-step process. Alternative methods employ a magnetic field, , mechanical stretching, balloon inflation, or anchoring force arising from rubbed polymer layers , in order to align the mesogens upon cross-linking. Substantially, the cross-linking reaction under these aligning fields is a one-step process.…”

A Versatile Preparation Route for Thin Free‐Standing Liquid Single Crystal Elastomers

“…With this simple, new pathway, macroscopically ordered free-standing LSCE films are easily accessible having a thickness in the range of about 100 nm to 100 mm as outlined in Figure . orientation techniques. [7,8] Instead of UV-crosslinking via suitable functional side-groups, network formation is successfully realized by g-irradiation. Unfortunately, this elegant method requires an irradiation source that is not readily available.…”

“…The only problem of this method is the complex chemistry of the functional, linear polymers, and the spontaneous crosslinking at elevated temperatures. In a very similar manner, Talroze et al prepared linear LC polymers that can be macroscopically aligned following conventional orientation techniques 7,8. Instead of UV‐crosslinking via suitable functional side‐groups, network formation is successfully realized by γ ‐irradiation.…”