Optical Properties of Film Coated with Localized Fine Particles and Agglomerative Structure in Film

Abstract

PET films were coated with slurries consisting of various sizes of particles using spin coating. The clusters of particles were formed in the coated layer. We studied the correlation between the number of primary particles in the clusters predicted by Usui's suspension model and the optical properties. All coated films showed a correlation between the number of primary particles and the opacity or transmittance. Especially for the primary particles with diameters of 13 and 6μm, we found a strong correlation with the coefficient of correlation higher than 0.9. On the other hand, the structure of film coated with 2μm particles changed during the drying process and the area occupied by the particles was decreased. Introducing a correction in the transmittance by the area decreased, we also obtained a strong correlation even for 2μm particle coated film.