Analysis of Adhesion and Optical Properties of Composite Powder Using Monodispersed Fine Particles and Its Application to Foundation

Abstract

We prepared composite powder called “ordered mixture (OM)” by mixing spherical particles (nylon) and monodispersed fine particles (PMMA) with the ratio of 2 : 1 in weight. Since this composite powder had been found to cover pores of human face efficiently, we investigated its adhesion and optical properties in detail using pore model of human face.
From SEM observation of OM-applied pore model, it was revealed that nylon filled pores while PMMA adhered uniformly at ridge. As a result, brightness increased at pores and decreased at ridge. It was considered that the pores were overshadowed because of this reduction of brightness difference around the pores. The increase of brightness at pores was considered to be caused by an ordinary reflection of nylon.
On the other hand, the decrease of brightness at ridge was a unique phenomenon. We suggested that a uniform PMMA layer suppressed reflection at ridge similar to anti-reflection layer of which refraction index changed continuously. The simulation of multi-interference layer suggested that if the refraction index of the particle was low (≤1.7) and the particle diameter was dose to 0. 4μm, its uniform layer would suppress reflection efficiently.