X-ray reflectivity measurements reveal anisotropy of the vertical surface roughness caused by exposure to linearly polarized UV (LPUV) light in the films of two azopolymers. The irradiated surface is found to have higher roughness in the direction parallel to the direction of polarization than in the orthogonal direction. The photo-modification of the surface morphology is caused by spatial changes induced in polymer films by LPUV irradiation. The important role of surface roughness anisotropy in determining the alignment of liquid crystals is discussed.
Yaroshchuk, O. V.; Agra, Deña Mae G.; Zakrevskyy, Yu; Chien, L.-C.; Lindau, J.; Kumar, Satyendra (2001). Anisotropic Surface Morphology of Azopolymer Films Generated by Polarized UV Light Irradiation. Liquid Crystals 28(5) 703-707. doi: 10.1080/02678290010022137. Retrieved from https://oaks.kent.edu/article/anisotropic-surface-morphology-azopolymer-films-generated-polarized-uv-light-irradiation