Formation et structuration de films azopolymères sur substrats liquides pour applications optiques et dynamiques

Azopolymer thin films exhibit remarkable photoresponsive properties due to the trans-cis isomerization of azobenzene molecules under light irradiation. These properties enable the formation of surface relief gratings (SRGs), a self-organized process with numerous applications in photonics, data storage, and microfabrication. Although SRGs on solid substrates have been widely studied, their formation on liquid substrates remains poorly explored. This thesis investigates the formation and structuring of azopolymer films on liquid substrates. The influence of parameters such as surface tension, viscosity, temperature, and container size on film spreading, SRGs formation, and optical responses is analyzed. We also explore the dynamic interactions between these films and Faraday waves, which induce periodic deformations on the liquid interface, thus opening new possibilities for structuring. A part is devoted to the writing, erasure and reconstruction of SRGs under polarized laser irradiation. The mechanisms governing these reversible processes are examined. In addition, we study the propagation and coupling of light at different liquid interfaces, including the diffraction of SRGs at the air-liquid and liquid-liquid boundaries. Finally, we highlight potential applications in photonics. The integration of fluorescent microplastic particles allows exploring the fluorescence enhancement effects at structured interfaces.