Intrinsically High Refractive Index Silicone Polymers Containing S and P Heteroatoms

There is growing interested in high refractive index polymers due to their numerous applications in optical materials. In current work, we reported a facile strategy to improve the refractive index of the optical materials. The new asymmetric binary thiol dopants containing high molar refractive index heteroatoms (S and P) and large conjugated groups were successfully designed and synthesized. Using these additives, the high refractive index silicone polymers were developed from these dopants and vinyl silicones simply via the light-cured reaction. The effects of dopants’ structure and content on the thermal and optical properties of cured silicone polymers were systematically investigated. The results show that the asymmetry structure of the dopants can not only effectively offset the accumulated trend of the large conjugated groups but also improve the refractive index of cured silicone polymers. Even with 5% dopant’s loading, the refractive index of the SOV-5 increased from 1.5773 to 1.5803 without notably sacrificing its the light transmittance. The glass transition temperature of the cured silicone polymers decreases, even though their crosslink density increase with the growing of the dopants’ loading.