Development Of Hydrophobic Polymer With Zwitterionic Precursors

Nonspecific protein adsorption resistance is one of the most important material properties to reduce the foreign body reaction of implants and biological adhension as marine coatings. Recently, zwitterionic polymer materials, considered as one of the most valuable nonfouling materials, were intensively investigated to answer the feasiblity of these materials in application. Compared with convencient zwitterionic materials, zwitterionic precursor materials have better water resistence and mechanical strength, which also has strong hydration ability after hydrolysis. Our lab has designed a kind of polyurethane material with zwitterion precursors, but its hydrophobicity and mechanical properties couldn’t meet the application requirements. In this research, zwitterion precursor contained silicone and polyurethane were designed, to improve the water resistence of nonfouling coatings. The results indicate:1. Through hydrosilylation of silicone and the ring-open reaction of epoxide group, zwitterionic precursor was introduced into PMHS. The silicone material was developed via the crosslinking of HDI, which showed low nonspecific protein adsorption after the interfacial hydrolysis of zwitterionic precursor. The introduction of zwitterions in hydrophobic silicone, which could cause severe protein adsorption, can realize the combination of nonfouling property and good water resistence. The swelling performance test also showed that the product could maintain its shape and mechanical strength within 6 months when soaked in weak alkalinity environment.2. Carboxybetaine ester analogue with ethyl substituted tertiary amine （ECBE） was synthesized as hydrolyzable precursor to improve the low hydrophobicity of carboxybetaine ester analogue with methyl substituted tertiary amine （MCBE）. With 3-mercapto-1.2-propanediol as the chain transfer agent, pECBE（OH）₂ was prepared by free radical polymerization. Polyurethane with hydrophobic zwitterionic brush side chains （pECBE-PU） was developed via the polymerization with HDI and the chain extender BDO. After the hydrolysis of ester group, a nonfouling zwitterionic layer occurs on surface pECBE-PU coating, which showed low nonspecific protein adsorption, HUVEC attachment and good bulk hydrophobicity. This also proves that ECBE still maintains good nonfouling ability.3. Different ratios of PTMG was introduced to improve the uniformity of surface, mechanical strength and elasticity of the pECBE-PU. The prepared pECBE-PTMG-PU showed better water resistence and mechanical properties, which could indicates high feasibility in the field application of marine nonfouling and biomedical coatings.