K. Usami et al., Influence of molecular structure on anisotropic photoinduced decompositionof polyimide molecules, J APPL PHYS, 89(10), 2001, pp. 5339-5342
We have investigated the anisotropic decomposition of polyimide molecules i
nduced by irradiation of linearly polarized ultraviolet light (LPUVL). Thre
e polyimides were examined: poly [4,4'-oxydiphenylene-pyromellitimide], pol
y [4,4'-oxydiphenylene-1,2,3,4-butanetetracarboximide] and poly [4,4'-oxydi
phenylene-1,2,3,4-cyclobutanetetracarboximide] (CBDA-ODA). Anisotropic deco
mposition was monitored by measuring the polarized infrared absorption spec
tra of similar to 10 nm thick films as a function of LPUVL exposure. Among
the three polyimides, CBDA-ODA showed the largest anisotropy of decompositi
on in the initial stage of LPUVL exposure. This result suggests that CBDA-O
DA is a suitable polyimide material for photoinduced liquid crystal alignme
nt based on photodecomposition reactions. The details of the LPUVL exposure
dependence of the film anisotropy are discussed. (C) 2001 American Institu
te of Physics.