Macromolecules, Vol.51, No.14, 5392-5400, 2018
Photoinduced Reorientation and Surface Relief Formation in Diblock and Random Copolymers with Benzoic Acid and Alkyloxy Side Groups
Diblock and random copolymers are synthesized from a methacrylate with benzoic acid (BA) side groups and a n-butyl methacrylate, and the photoinduced reorientation of thin films doped with a N-benzylideneaniline carboxylic acid (NBA), which governs the H-bond with BA, is investigated using linearly polarized (LP) 365 and 313 nm light. A sufficient thermally stimulated photoinduced orientation of the BA side groups and simultaneous sublimation of NBA are attained for the diblock copolymer films, whereas a thermal treatment results in the random orientation of the random copolymers. Furthermore, surface relief (SR) formation of the film is explored when the NBA-doped films are exposed to LP light using a photomask. The liquid crystalline characteristics, thermal properties, axis-selective photoisomerization, and the photo-cross-linking of the film play important roles in the molecular reorientation and SR formations.