Substituting Commercial Wetting Agents With Bio‐Based Gemini Surfactants: Performance and Sustainability Evaluation

ABSTRACT The development of eco‐friendly, high‐efficiency surfactants is critical for advancing sustainable waterborne coatings. In this study, a novel Gemini surfactant (TA‐TD) was synthesized via solvent‐free esterification between tung oil acids (TA) and 2, 5, 8, 11‐Tetramethyl‐6‐Dodecyne‐5, 8‐Diol Polyoxymethylene Ether (TDDPE). Structural analysis (FTIR, 1 H NMR, GPC, GC–MS) confirmed complete reaction and successful molecular integration at an optimal TA:TDDPE ratio of 2:1. Compared with a commercial wetting agent (CAB‐35, FMES, Tween‐80 and 1227), TA‐TD‐2.0 demonstrated superior performance, including lower critical micelle concentration (CMC), faster dynamic surface tension reduction, and significantly reduced contact angle on hydrophobic substrates. Furthermore, TA‐TD‐2.0 improved coating gloss, water resistance, and salt spray durability, while maintaining excellent defoaming properties and low VOC compatibility. These advantages stem from its unique Gemini structure and long‐chain hydrophobicity derived from renewable tung oil. The combination of high efficiency, multifunctionality, and sustainable sourcing highlights the commercial potential of TA‐TD as a next‐generation green surfactant for environmentally responsible coating systems.