Development of Robust and Recoverable Ultralow-Fouling Coatings Based on Poly(carboxybetaine) Ester Analogue

Polyurethane with zwitterionic side chains (PCB-ester-PU) based on a poly(carboxybetaine) ester analogue is developed for marine coatings and biomedical applications by introducing dihydroxy-terminated PCB-ester(OH)2 with different polymerization as the macrodiol, 4,4'-diphenylmethane diisocyanate (MDI) as the diisocyanate, and 1,4-butanediol (1,4-BD) as the chain extender. Robust coatings are obtained and exhibit long-term excellent resistance to nonspecific protein adsorption, bacterial adhesion, and human umbilical vein endothelial cell (HUVEC) attachment after hydrolysis. Tests of adhesion on different substrates and film hardness indicate that the material possesses far more stable mechanic properties than hydrogel coatings. Moreover, such a resistance can be generated not only by alkaline solution, but also by a physiological buffer (such as phosphate-buffered saline (0.15 M pH 7.4 PBS)) or by steam in an autoclave. Ultimately, its excellent long-term nonfouling property, its healing capability through self-regeneration and superior mechanic properties (such as hardness and elasticity), and its good adhesiveness as a paint on both polar and nonpolar substrates make this material an ideal candidate as a coating for marine and medical devices.