Birefringence control of alignment film of liquid crystal polymer with N-benzylideneaniline by in situ reaction

Abstract

Photoinduced molecular reorientation of liquid crystalline polymer containing N-benzylideneaniline (NBA) side groups was investigated by irradiation of linearly polarized UV (LPUV) light and subsequent annealing. Recently, we reported photoalignable polymer with phenylbenzoate side groups (P0) exhibited high birefringence. Hydrolysis of this film converts the C=N bond to aldehyde end groups and orientation of the polymer is reserved. Furthermore, in situ reaction of amine and aldehyde end groups introduced deferent type of NBA. Although birefringence of the film after hydrolysis is reduced, introduction of 2-aminofluorene (AF) to the film increases the birefringence up to 0.34.