Electrooptical light-management material: Low-refractive-index hydrogels

A prototype synthetic hydrogel that has a low refractive index (<1.35) and is optically clear has been developed [1]. The refractive index is a key feature in the application of optical polymers, and this hydrogel is particularly useful for light-transmitting devices. The ultraviolet-light-curable hydrogel formulation contains more than 90% water (plus water-soluble oligomers, photoinitiator, and surfactant). UV cures it instantly at 425 mJ/cm(2) at a thickness of less than 10 mm, giving a firm hydrogel with a modulus of 2.3 x 10(3) dyn/cm(2). This hydrogel has utility in light-management applications.