The photoreactive thin films of poly(oxyalkyleneoxy-1,4-phenylenediacr
yloyl), a PDA-n polyester (n=2-5), were prepared. Their photoreactions
and the liquid crystal (LC) photoalignment by irradiation of linearly
polarized UV light (LPL) were investigated. The PDA-n polyesters have
photoreactive sites in the polymer main chain and not in the side cha
in which is different from poly(vinyl cinnamate) (PVCi), a well-known
photoalignment polymer. These PDA-n thin films show different photorea
ctivities depending on the number of methylene units, n. Odd-numbered
PDA-n polyesters with higher photosensitivity than even-numbered PDA-n
. polyesters show a dichroism due to irradiation with LPL which result
s in a homogeneous alignment of the nematic LC.