Fabrication and anti-oil/antifogging performance of zwitterion-bearing silicate coatings

Zwitterions were grafted to silicate networks by co-condensation using SBSi. • High hydrophilicity was achieved based on LK23 silicate and 15 wt% SBSi. • Optimized coating exhibited anti-oil performance under both wet and dry conditions. • Coating removed viscous oils and residues by simple water rinsing or immersion. • Coating showed excellent antifogging performance under varied fogging conditions. The development of anti-oil-fouling coatings is vital for applications ranging from industrial equipment to domestic kitchen appliances. In this study, anti-oil/antifogging coatings were fabricated by grafting zwitterions to silicate networks through the co-condensation of a sulfobetaine zwitterionic siloxane with silicate. Effects of the composition of silicate coatings, the content of zwitterions on the surface hydrophilicity, optical properties, durability of hydrophilicity, and anti-oil/antifogging performance of coatings were systematically investigated. Introduction of zwitterions favored the coating compactness as well as the enhanced surface hydrophilicity. Importantly, the ratio of lithium silicate-to-potassium silicate strongly influences the durability of hydrophilicity. High surface hydrophilicity, i.e., water contact angle below 10°, could be well maintained at 2:3 of lithium silicate-to-potassium silicate mass ratio even after 168 h of water immersion. The optimized zwitterion-bearing coating reduced the underwater oil adhesion force from 8.8 μN to 0.5 μN, confirming outstanding underwater anti-oil capability. More interestingly, the coating rapidly and completely detached viscous vegetable oil and oil fumes adhered under dry conditions through simple water rinsing or immersion. The coating also exhibited outstanding anti-fogging performance under wide spectrum of conditions. After 1000 cycles of steel wool abrasion, the optimized coating still maintained strong hydrophilicity and anti-oil-fouling performance, highlighting its promise for practical applications. Download: Download high-res image (267KB) Download: Download full-size image