Highly durable antifogging coatings resistant to long-term airborne pollution and intensive UV irradiation

Antifogging coatings have tremendous application potential as they can prevent undesired fogging and blurring on transparent substrates when exposed to humid environment. However, most antifogging surfaces suffer from poor durability and tend to lose the antifogging property in the short term caused by airborne pollutant adsorption or environment weathering (e.g., UV irradiation). To address this issue, a series of zwitterionic and hydroxylated superhydrophilic coatings were prepared and their long-term antifogging properties under harsh conditions were systematically studied, including in a normal laboratory environment, under accelerated pollution test by exposing surfaces to acetic acid steam, and under UV irradiation. The prepared zwitterionic coatings showed significantly improved durability than the hydroxylated surfaces in all the test conditions, attributed to the chemical inertness and stability of the zwitterionic moieties. By incorporating zwitterionic coating and nanoscale roughness together, the longevity of antifogging surfaces can be further greatly improved, and eyeglasses treated with such nanostructured zwitterionic coating kept decent antifogging property even after storage for up to 210 days. The present nanostructured zwitterionic coatings are promising for real-world antifogging applications that can survive practical environmental fouling and weathering.