Surface hardness and transparency of poly(methyl methacrylate)-silica coat film derived from perhydropolysilazane

To prepare hard and transparent poly (methyl methacrylate)-silica coat film on glass or polycarbonate substrates, poly(methyl methacrylate-co-2-hydroxyethyl methacrylate) random copolymers and perhydropolysilazane (PHPS) were blended in solution. Then the solution was cast on the substrates. The grafting of PHPS onto 2-hydroxyethyl methacrylate unit was analyzed by 1 H NMR spectroscopy. Surface hardness and transparency of the coat film were measured by nano-indentation method and UV-Vis spectroscopy, respectively. Surface hardness of coat film depended on the volume fraction of silica in the coat film, and reached 2.7 GPa when the volume fraction of silica was 76.4%. Transparency of the coat films prepared with PHPS was almost 100%, indicating that the coat film prepared with PHPS was highly transparent not only on glass substrate but also on the polycarbonate substrate.