Fabrication of photo-responsive moth eye-like patterned poly(vinyl alcohol) films selectively containing TiO2 nanoparticles in the microdome

Moth eye-like patterned poly(vinyl alcohol) (PVA) films selectively containing titanium dioxide (TiO2) nanoparticles in the microdome were fabricated using polystyrene honeycomb patterned porous film as a template in which TiO2 nanoparticles are pore-filled. The template was prepared by in situ pore filling of TiO2 nanoparticles by the modified breath figure method, wherein the hydrolysis of titanium butoxide was performed in the condensed water droplets as microreactors. The moth eye-like patterned PVA film selectively containing TiO2 nanoparticles in the microdome was transparent almost similar to the pristine PVA flat film. However, the film showed a reversible photochromism that changes to blue color by UV illumination and recovered by visible light. The obtained films may have potential applications in anti-reflective surfaces, photo-catalytic surfaces, opto-electronics, and photo-catalytic devices. (C) 2018 Elsevier Ltd. All rights reserved.