High Refractive Index Polymers by Design

We show that key parameters of high refractive index (HRI) polymers may be accurately predicted based on the data of the HRI group and the polymer backbone comprising the spacer (S) and polymerizable group (PG). Five different HRI groups and the corresponding siloxane and methacrylate homopolymers were considered in this work. As a testbed we have chosen HRI polymers for ophthalmological implants, e.g., intraocular lenses, defining the figures-of-merit. In this case they need to be nonabsorbing throughout the visual wavelength range and should have a high refractive index nD and a high Abbe number νA as well. Finally, a low glass transition temperature Tg is required to receive flexible materials. All ten HRI polymers, among them five prepared first within this study, were synthesized and characterized. The received properties match the predicted within percentage range and show that the straightforward design principles introduced here are highly productive tools for polymer design.