An eco-friendly and durable anti-fogging coating based on sulfobetaines and silicones

Fogging on transparent materials may severely obstruct vision, resulting in many problems such as energy consumption and safety hazard. Superhydrophilic coatings can effectively prevent fogging by facilitating the formation of a uniform and continuous water film. However, superhydrophilic coating usually suffers from organic solvent usage and its vulnerability in high-humidity environments due to excessive water absorption. In this work, a water-based durable anti-fogging coating has been prepared with a copolymer (P(SBMA-co-VTHS)), which is fabricated with [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide (SBMA) and vinyl trihydroxy silane (VTHS). As the main component, SBMA is superhydrophilic, while VTHS allows the copolymer to establish covalent bonds with the glass. Benefiting from the delicate balance between superhydrophilicity and durability, glass coated with P(SBMA-co-VTHS) could maintain excellent transparency in hot vapor (80 °C) for 8 h. Meanwhile, the light transmittance of coated glass remained above 85 % even after 40 cycles of tape peelings. In addition, the P(SBMA-co-VTHS) coating showed superior self-cleaning performance due to its superhydrophilicity, which is meaningful for practical applications.