Robustly transparent photothermal icephobic coating via facile in situ PDA polymerization and PDMS brushes grafting

Icing or frosting on transparent surfaces pose significant challenges for the reliability of optical devices. Although various transparent photothermal coatings have been proposed to alleviate ice accumulation via solar-induced surface heating, their limited fabrication strategy and mechanical stability greatly constrain practical implementation. In this study, we present a facile and effective in situ polymerization method to fabricate a transparent, photothermal, and mechanically durable anti-icing coating. The coating is fabricated through in situ polymerization of polydopamine (PDA) onto transparent substrate, which is then followed by the surface grafting of polydimethylsiloxane (PDMS) brushes. In this coating system, PDA not only serves as a proficient solar-thermal converter and but also supplies an abundance of catechol groups for subsequent PDMS grafting. By tuning the PDA deposition time, the light transmittance and photothermal performance of the coating was precisely controlled. Under 1 sun irradiation, the PDA 24 @PDMS coating increases the surface temperature of 26.2 °C in −20 °C surroundings, while retaining a high transmittance of 64.8 % at 550 nm. Furthermore, after grafting PDMS brushes, the coating presents excellent oleophobic, self-cleaning and icephobic properties. More importantly, the incorporation of PDMS brushes reduces the PDA@PDMS surface friction coefficient (∼ 0.1) and improves the surface abrasive resistance that can endure over 9000 abrasion cycles. This study highlights a facile fabrication approach for the practical application of multifunctional transparent photothermal anti-icing coating in harsh environments.