Simultaneous radical and condensation polymerization for the fabrication of cost-effective, transparent, and underwater oil-repellent hybrid films

Abstract

Underwater oil-repellent surfaces are crucial for various applications that require protection against oil-based contaminants in aquatic environments, yet producing cost-effective, crack-free, and transparent coatings with such properties remains a major challenge. In this study, a one-pot, two-step synthesis approach was used to fabricate transparent, underwater oil-repellent coatings by synthesizing a hybrid organic–inorganic copolymer (PAA–TEOS) through simultaneous radical and condensation polymerization of acrylic acid (AA) and TEOS alkoxysilane. The AA/TEOS molar ratio and TEOS addition timing were optimized to obtain crack-free films, and wettability was evaluated by measuring water contact angles in air and hexadecane contact angles underwater. Surface morphology and roughness were characterized using SEM and AFM. The optimized hybrid coatings exhibited high transparency, superhydrophilicity in air (water contact angle ≤10°), and superoleophobicity underwater (hexadecane contact angle >160°), while resisting cracking and maintaining structural integrity in aqueous environments. These characteristics make them highly suitable for marine antifouling, underwater sensors, and oil–water separation applications, offering a scalable and eco-friendly alternative to conventional coatings.