Temperature-triggered switchable superwettability on a robust paint for controllable photocatalysis

Superwettability and photocatalysis are two important properties in interfacial science. Photocatalysts with stable (super)hydrophilicity and (super)hydrophobicity have been widely studied. However, to endow long-term switchable superwetting and photocatalysis on the same surface is rarely reported. Here, we prepare temperature (T)-triggered superwetting transitions on a paint for controlled photodegradation. The superwetting switches can be reversibly cycled 50 times after sandpaper abrasion, knife scratch, finger wipe, and ultra-long UV irradiation. Meanwhile, UV resistance ensures long-termed coexistence of switchable superwetting and photocatalysis. As for water-based dyes (methyl blue, methyl orange), our paint shows T-regulated photodegradation. The superhydrophobic surface at 50°C possesses less-contacted catalytic sites and exhibits the lowest degradation rate (DR), 15.0%. Inversely, the highest DR of 95.5% is obtained on a 10°C-sensitive superhydrophilic surface because of the sufficiently contacted catalytic sites. This work indicates promising applications in various fields of materials science and chemistry.