Superhydrophilic Polymer Brushes with High Durability and Anti-fogging Activity

Hydrophilic surface coatings have made it into commercial application as possible solutions for problems such as fogging, frosting, and biofouling. However, there is an inherent contradiction: superhydrophilic coatings can prevent these unwanted phenomena, but they are also readily dissolved by water. To address this longevity concern, the present work introduces a fully aqueous surface-initiated (SI) polymerization under ambient conditions for the facile formation of durable superhydrophilic polymer coatings. The aqueous SI photoinduced electron transfer reversible addition-fragmentation chain transfer polymerization (SI-PET-RAFT) approach developed herein uses water as a sole solvent and can be performed in an ambient air atmosphere. This circumvents traditional shortcomings in SI radical polymerization related to limited hydrophilic monomer solubility in organic solvents and oxygen tolerance. In addition, polymerization under mild yellow light eliminates possible substrate degradation that can occur with conventional thermal or UV-light treatment. The cationic, anionic, and zwitterionic polymer films engineered in this study show promise as functional materials with enhanced durability, demonstrated to effectively combat the challenge of surface fogging. The described approach is user-friendly, cost- and time-efficient, and scalable and produces efficient anti-fogging coatings that outperform commercial solutions in both optical quality and durability.