High-Performance and Simply-Synthesized Ladder-Like Structured Methacrylate Siloxane Hybrid Material for Flexible Hard Coating

Abstract

A high performance ladder-like structured methacrylate siloxane hybrid material (LMSH) was fabricated via simple hydrolytic sol-gel reaction, followed by free-radical polymerization. A structurally ordered siloxane backbone, the ladder-like structure, which is an essential factor for high performance, could be achieved by a short period of sol-gel reaction in only 4 h. This results in superior optical (Transmittance > 90% at 550 nm), thermal (T-5 wt % decomposition > 400), mechanical properties(elastic recovery = 0.86, hardness = 0.6 GPa) compared to the random- and even commercialized cage-structured silsesquioxane, which also has ordered structure. It was investigated that the fabricated ladder-like structured MSH showed the highest overall density of organic/inorganic co-networks that are originated from highly ordered siloxane network, along with high conversion rate of polymerizable methacrylate groups. Our findings suggest a potential of the ladder-like structured MSH as a powerful alternative for the methacrylate polysilsesquioxane, which can be applied to thermally stable and flexible optical coatings, even with an easier and simpler preparation process.