Highly Transparent and Tough Filler Composite Elastomer Inspired by the Cornea

We propose a strategy to develop a colorless, transparent, and tough composite elastomer inspired by the cornea, which is the transparent front portion of the eyeball. The composite elastomer, in which 34 vol % hard silica particles with a uniform particle size are dispersed as a filler in a low-crosslinking polymer network exhibits a fracture energy that is ∼13.5 times higher than that of a system without the silica particles. This strategy also makes the elastomer optically transparent, because the light scattered by each silica particle that forms an ordered structure in the polymer network is cancelled by interference. This research may pave the way for the development of optically transparent and durable materials for applications such as advanced medical devices and soft robots.