Influence of Photoanisotropies on Light-Controllable Structuration of Azopolymer Surface

The capability to optically control surface structuration of azopolymer films is an important goal in different research fields, enabling remote activation and tuning of associated processes mediated by the surface. In this work, two amorphous azopolymers, structurally engineered in order to exhibit linear and circular photoinduced optical anisotropies, have been investigated, with the aim to design complex light-reconfigurable topographical structures. Different intensity and polarization patterns were generated by two- or four-beams interferometry and inscribed on the polymer films. Relief depths in the range of hundreds of nanometers have been produced, mediated by the bulk photoinduced anisotropies of the materials. It is shown that, on the basis of the kind of light patterns (intensity and/or polarization), depth and shape of the relief grating can be tuned. Polymers with higher photoinduced birefringences enable one to produce deeper reliefs. Bidimensional light polarization patterns generate complex surface structures, even with chiral features, envisaging the possibility to engineer large area opto-controllable surfaces and platforms.