Light-Tunable Solvent Drying in Photo-Responsive Solution Coatings

Solvent drying rate of azobenzene/acetone solution coating was tunable by linearly polarized UV light. The light exposure promotes the photo-induced conformational change of azobenzene from its trans to its cis form, as well as the molecular alignment perpendicular to a polarization direction. Drying experiments of the photo-responsive solutions revealed that angled irradiation of s-polarized light showed a peculiar angle-dependent drying behavior, while no dependence was observed for the p-polarized light irradiation. The photo-induced solvent drying was observed in a particular range of azobenzene weight fractions and UV light intensities, suggesting a promising way to tune solvent drying rates by light.