Hierarchical Photocomposition of Heteronanostructures in a Surfactant–Polysiloxane Hybrid Film toward Next-Generation Nanolithography

Surfactant-templating organic–inorganic hybrid systems that can lead to mesoporous silica have been widely studied. Control of the initial composition of the precursor solution is essential to create the desired nanostructure. We propose herein a polysiloxane-based organic–inorganic hybrid system that shows phase transitions among lamellar, hexagonal, and spherical surfactant-based nanostructures by changing the atmospheric humidity. By utilizing a thiol–ene click photoreaction, a shear-aligned hexagonal structure is fixed, and the humidity-sensitive phase transition is hampered. Patterned UV curing provides local in-film conversion of the nanostructure in the shaded areas, leading to fabrication of patterned films composed of coexisting different nanostructures (heteronanostructures) via humidity alternations. For the lamellar ⇄ hexagonal phase transition in lower humidity conditions, reversible birefringent image changes are observed due to the orientation memory effect of the lamellar phase. In contrast, in the hexagonal ⇄ spherical micelle case in higher humidity conditions, the orientation memory is lost via the fluid micelle phase, resulting in randomization of the nonirradiated regions. The successful multifarious photocomposition is expected to provide wider possibilities toward next-generation nanolithography.