Two kinds of TiO_2 filled epoxy coatings were designed and prepared to obtain pigments with different dispersion degrees of TiO_2 particles.Laser scanning confocal microscope(LSCM)was used to investigate both the horizontal and vertical distributions of TiO_2 particles in the coatings.The results indicated that TiO_2 in the two samples shared considerable similarity in horizental dispersion,but exhibited great difference in vertical dispersion.TiO_2 showed uniform vertical distribution in disp coating,wheras a gap about 1.1μm was found in the non-disp coating,which significantly influenced the surface optical properties of the coatings during weathering.Based on the confocal data,the model of dispersion of pigments in the coatings was proposed and the change of surface properties during weathering was predicted:the surface optical properties showed an initial decrease followed by a subsequent increase,which was in good agreement with the weathering data.
