A self-assembled, silicone acrylate coating formulation and detection of the optically non-uniform structure with reflectance spectroscopy

Abstract

A newly synthesized, single-step silicone acrylate formulation cured by conventional radiation produced a reflection spectrum that showed an unusual interference pattern for a single-step coating. The acrylate was prepared by transesterification of silicate oligomer with ω-functionalized acrylic alcohol. The reflectance spectrum was analyzed by means of the Fourier transformation, followed by a separation of variables and constrained conditions. The separation of variables was based on the refractive index as a function of the layer depth, which revealed the coating was non-uniform in refractive index. An interface within the coating was independently observed by microscopy, showing that the coating separated into two layers, supporting the numerical analysis. Although the coating was manufactured by a single-step coating process, the two-layer structure that was formed is normally constructed with multiple coating processes, such as applications of a primer and a top coat. Experiments varying the formulation components show that the new silicone acrylate and an aliphatic di-functional acrylic ester were essential components for the formation of the two-layer structure. Outdoor weathering results are presented after 1 year of testing in Florida and Arizona, which showed better performance than conventional coating systems.