Eco-friendly covalently connected silicone hydrogel with negatively charged surface for marine anti-biofouling

In this study, a silicone hydrogel (Gel-TA-Si-x) with amphiphilic and negatively charged surfaces was prepared by combining low surface free energy silicone with highly hydrophilic hydrogel materials using the method of one-step solvent-free bulk polymerization. The hydrogel films exhibited good mechanical properties. This was primarily reflected in the high tensile strength (1 MPa) and elongation at break (358.1 %). Notably, the film exhibited increased hydrophobicity, higher water contact angle and gradual decline in water absorption rate as the mPDMS monomer dosage increased. Despite this, the surface free energy remained low at 22.1 mJ m −2 , indicating effective fouling release capability (removal strength against pseudobarnacles was 0.16 MPa). In addition, the surface zeta potential of the hydrogel was as low as −86 mV (at pH = 10). Laboratory antifouling performance tests indicated that the surface negativity of the material enhanced its static antifouling performance and the hydrogel with a negatively charged surface exhibited high bacterial adhesion resistance of 93 % and good resistance to Chlorella adherence and biofilm inhibition. Favorable anti-fouling performance was observed after 180 d of marine field testing. Moreover, the covalent connection of silicone monomers with hydrogel monomers through copolymerization create a stable three-dimension crosslinking network, thereby improving the durability of materials in complex marine environments. This study provides a new idea for developing efficient and environmentally friendly silicone hydrogel antifouling materials.