Controlling Transmittance of Visible Light by the Incident Light Angle Using Needle-like TiO2 Particle Arrayed Composite Films

Composite films with an array of needle-like TiO2 particles in urethane resin matrix were fabricated by applying a 1 kHz AC bias with a square wave. In the resulting film, needle-like TiO2 particles were arrayed in the composite films in a direction normal to the film surface. The composite films showed angular dependence of transmittance in the visible-NIR range. For the composite film with arrayed 0.1 vol% TiO2 needle-like particles, the transmittance changed by 16.6% between 0° and 60° at a wavelength of 500 nm.