Photo-orientation in LB multilayers of amphotropic polymers

Amphotropic polymers with photochromic azobenzene side groups like 2-hydroxyethyl polyacrylates and ''hairy rod'' polyglutamates combine amphiphilic and thermotropic properties. Upon UV irradiation the initial double layer structures were irreversibly destroyed by the E-Z photoisomerization. New ordered structures with modified spacing, in-plane anisotropy and surface topology were generated by a subsequent Vis irradiation step. Optical anisotropy was modified due to a photo-orientation process on irradiation with linearly polarized Vis light. Relations between photoinduced modification and thermotropic self-organization are demonstrated for Langmuir-Blodgett (LB) layers of both types of polymers. The dependence of the photoinduced reorientation process on the structure, supermolecular order and the aggregation of the azobenzene moieties is shown for the different ordered LB systems.