Preparation of highly transparent poly(meth)acrylates with enhanced refractive indices by radical (co)polymerization of seleno(meth)acrylates

Over the years, selenium-containing polymers have attracted increasing interest as high-refractive index materials. In this study, two transparent high-refractive-index polymer series were prepared by the radical polymerization of phenyl selenomethacrylate (PhSeM) and phenyl selenoacrylate (PhSeA), and their copolymerization with methyl methacrylate (MMA). The refractive indices of the poly(PhSeM) and poly(PhSeA) homopolymer films were 1.6426 and 1.6519, respectively at 589 nm with Abbe numbers in the range 27.2-24.1, making them ideal monomers for improving the refractive indices of (meth)acrylate-based copolymers. By increasing the MMA content, the refractive indices of these copolymers were reduced from 1.6207 into 1.5181 with Abbe numbers in the range 25.7-53.1. Both homopolymers exhibited excellent transmittances (>94%) at the wavelength 400 nm. Moreover, owing to their higher MMA content, the selenium-containing copolymers exhibited a higher transparency (95-99%) than the homopolymers, which is highly desirable for optically transparent materials.