New organic-inorganic hybrid materials: high refractive index polymers based on cyclotriphophazene with high thermostability and transparency

Two flexible and colorless high refractive index films based on cyclotriphophazene have been successfully prepared by the thiol-ene reaction of hexa-substituted cyclotriphophazene monomer (CVP) and commercial bifunctional aromatic thiol. The new organic-inorganic hybrid polymers exhibit high transmittance of 89% varying from 550 nm to 2000 nm and transmittance is still more than 87% even at 2500 nm, as well as good thermostability with a 5% weight loss temperature (T-5d) of over 320 degrees C and a glass transition temperature (T-g) of up to 163 degrees C. Moreover, the polymers show high refractive indices (n) of 1.673 and 1.706 at 550 nm. In particular, the polymers also display stable optical properties with a transmittance of 88% and n of 1.673, 1.701 at 550 nm, even after immersing them in water at room temperature for 2 days. In addition, the polymers exhibit good mechanical properties and dimensional stability. These data indicate that the new inorganic-organic hybrid polymers are desirable as optical encapsulation resins for light-emitting diode (LED) devices and antireflective coatings.