Synthesis of UV-curable urethane acrylate–TiO2 hybrid films with enhanced refractive index and optical clarity via sol–gel and surface modification

Abstract The UV curable Multifunctional Urethane-Acrylate resin was prepared through a chemical reaction using Isophorone Diisocyanate and Pentaerythritol Triacrylate. The TiO2 was synthesized via a sol-gel reaction and then used 3-(trimethoxysilyl) propyl methacrylate to surface treatment for increased compatibility with MUA resin and enhanced the materials of refractive index. Traditional composite materials have a combination of organic and inorganic structure. The interaction on the organic and inorganic interface mainly depends on physical forces like Hydrogen bonding or Van der Waals forces, which are relatively weak compared to covalent or ionic bonds. Consequently, the interface strength and contact area between organic and inorganic components affect the mechanical characteristics. In contrast, hybrid composite differs from composite materials in that they combine organic and inorganic substances at the nanometer scale, creating a molecular-level composite material. By utilizing van der Waals forces, hydrogen bonding, and chemical bonding, hybrid materials overcome the macroscopic phase separation observed in traditional composite materials. This allows them to exhibit the characteristics of both organic and inorganic materials, meeting the requirements for high-performance materials. The highest refractive index of the organic–inorganic hybrid material can reach 1.71.