Microstructure and Properties of Poly(ethylene glycol)-Segmented Polyurethane Antifouling Coatings after Immersion in Seawater

Polyurethane has a microphase separation structure, while polyethylene glycol (PEG) can form a hydrated layer to resist protein adsorption. In this paper, PEG was introduced to polyurethane to improve the antifouling properties of the polyurethane, providing a new method and idea for the preparation of new antifouling polyurethane materials. The mechanical properties, hydrophilicity, swelling degree, microphase separation and antifouling performance of the coatings were evaluated. The response characteristics of the polyurethane coatings in a seawater environment were studied, and the performance changes of coatings in seawater were tested. The results showed that the crystallized PEG soft segments increased, promoting microphase separation. The stress at 100% and the elasticity modulus of the polyurethane material also markedly increased, in addition to increases in the swelling degree in seawater, the water contact angle decreased. A total of 25% of PEG incorporated into a soft segment can markedly improve the antibacterial properties of the coatings, but adding more PEG has little significant effect. After immersion in seawater, the coatings became softer and more elastic. This is because water molecules formed hydrogen bonding with the amino NH, which resulted in a weakening effect being exerted on the carbonyl C=O hydrogen bonding and ether oxygen group crystallization.