Research progress of environmentally friendly degradable marine antifouling coatings

• The degradation reaction kinetic theory of degradable coatings is analyzed. • The layer-by-layer optimization strategy of molecular structures is summarized. • Multi-path synergistic degradable coatings as a future goal are discussed. • The advanced calculation methods for optimizing polymer design are highlighted. Marine biofouling, i.e., the attachment of biomaterial on the surfaces of submerged objects, has long been a serious hazard to marine economies and ecosystems. Environmentally friendly degradable antifouling coatings developed in the last decade or so can efficiently replace traditional toxic antifouling coatings based on the following advantages: full degradability, non-discriminatory resistance to fouling, low addition of antifouling agents, and high compatibility with other antifouling mechanisms. However, current research and few available reviews neglect the degradation reaction kinetics mechanisms, resulting in the development of degradable coatings remaining in an inefficient trial-and-error stage. Here, we take a different approach, starting from degradation kinetics theoretical models and combining advances in microscopic simulation and computational research to reveal the degradation and antifouling mechanisms of highly efficient degradable polymers. From the novel perspective of layer-by-layer molecular structure design, we comprehensively analyze the optimization pathways for ester units, molecular chains, and network structures during the evolution of degradable polymers from main-chain degradation types to hyperbranched degradation types. We also summarize the achievements and future challenges of multi-functional composite coatings that synergize with multiple antifouling mechanisms to address the demands of complex marine environments. This review provides the theoretical basis and optimization criteria for the future development of degradable antifouling coatings and indicates that advanced computational models and theories are likely to further accelerate the design of antifouling polymers.