Specific Ion Effects on the Enzymatic Degradation of Polymeric Marine Antibiofouling Materials

It is expected that the widely dispersed ions in seawater would have strong influence on the performance of polymeric marine antibiofouling materials through the modulation of enzymatic degradation of the materials. In this work, poly­(ε-caprolactone)-based polyurethane and poly­(triisopropylsilyl methacrylate-co-2-methylene-1,3-dioxepane) have been employed as model systems to explore the specific ion effects on the enzymatic degradation of polymeric marine antibiofouling materials. Our study demonstrates that the specific ion effects on the enzymatic degradation of the polymer films are closely correlated with the ion-specific enzymatic hydrolysis of the ester. In the presence of different cations, the effectiveness of the enzyme to degrade the polymer films is dominated by the direct specific interactions between the cations and the negatively charged enzyme molecules. In the presence of different anions, the kosmotropic anions give rise to a high enzyme activity in the degradation of polymer films induced by the salting-out effect, whereas the chaotropic anions lead to a low enzyme activity in the degradation of the polymer films owing to the salting-in effect. This work highlights the opportunities available for the use of specific ion effects to modulate the enzymatic degradation of polymeric antibiofouling materials in the marine environment.