Tyrosine-based branched polybenzoxazines with antibacterial and surface fouling released performances for marine antifouling coatings

To address environmental challenges from leaching antifouling agents in traditional coatings, developing antifouling coatings with inherently antibacterial properties is of significant value. In this study, the branched benzoxazines were synthesized from L -tyrosine-derived polyether amides and primary amines with diverse functionalities, and their antibacterial activities were assessed. Polybenzoxazine coatings (THB-PBOZs) were fabricated through the oxazine ring-opening curing process. The impact of amine functionality on coating properties was examined, including gel content, thermal stability , mechanical attributes, surface morphology , and adhesion ability. Notably, the A 3 + B 2 polybenzoxazine derived from 1, 12-dodecylenediamine (THB-PBOZs-DDA) exhibited superior characteristics, with a gel content of 86 ± 2.71 %, signifying a dense crosslinking. It demonstrated excellent mechanical strength , with a tensile stress of 3.3 ± 0.54 MPa and an elastic modulus of 32.11 ± 0.42 MPa. The THB-PBOZs-DDA coating, featuring a smooth surface and significant hydrophobicity (water contact angle of 133 ± 1.09°), adhered to substrates with a strength of 5.43 ± 0.11 MPa. The intrinsic antibacterial nature, combined with low surface energy and low modulus of THB-PBOZs coatings provided them with outstanding fouling-release attributes. In comparison, THB-PBOZs-DDA demonstrated superior overall performance against other reported antifouling coatings, highlighting its potential for broad application. The L -tyrosine-based polybenzoxazine antifouling coating offered an innovative and eco-friendly solution for marine applications. • Bio-based branched polybenzoxazine coatings was derived from L -tyrosine. • The functionality of primary amine affected the performance of coating. • The monomer THB-BOZs made the corresponding coating with antibacterial ability. • The inherent antibacterial abilities enhanced the fouling-release efficacy.