Structure optimization of epoxy MQ silicone resin for excellent transparency, wear resistance, and anti-smudge coatings

The demand for high-transparent functional coatings with excellent hardness and excellent anti-smudge properties has increased significantly, especially for display devices such as smartphones and tablets. In this work, epoxy MQ silicone resins with different epoxy values were synthesized by sol-gel method and hydrosilylation reaction, and then cured with methyl hexahydrophthalic anhydride to obtain an organic-inorganic hybrid coating with extraordinary transparency (99.3 % at 550 nm) and high hardness (0.21 GPa). By introducing fluorocarbon chains into MQ silicone resin, the surface energy of the coating is reduced from 31.9 ± 0.5 mJ/m² to 23.1 ± 0.3 mJ/m² and the water contact angle is increased from 84.0° to 107.9°, showing excellent self-cleaning properties while maintaining good mechanical properties (hardness, 0.19 GPa) and excellent transparency (98 % at 550 nm). Moreover, the coating could maintain its outstanding performance after 100 cycles of steel wool abrasion or heating at 60 °C for 60 h. Therefore, this work provides insights into the fabrication of multifunctional coatings integrated with high transparency, wear resistance, as well as anti-smudge properties for touch screens.