Control of Optical Characteristic by Coating and Drying

Abstract

Three slurries containing particles of different sizes were coated onto PET film. The rotation rate of the spin coating, which is known to control the structure of spherical particle sols, was varied in the range of 1000–5000 min⁻¹. The coated films were then dried by conduction, radiation or convection. The appearance of the coated film was observed and haze was measured as an optical characteristic of the film. The appearance and haze of films coated with particles of 2 μm or more in diameter were not affected by the drying method, but were affected by the rotation rate. On the other hand, those of films coated with 100 nm particle were strongly influenced by the drying method. Consequently, according to the size of the particle, by selecting the rotation rate or drying method, haze can be controlled.