Controlling the Marine Biodegradation Profile and Mechanical Properties of Poly(-caprolactone) with Hydrophobic Water-Responsive Linkages

The development and use of biodegradable polymers are highly anticipated as solutions for the global problem of plastic pollution. One of the major challenges with biodegradable polymers is the inherent trade-off between degradability and mechanical reliability. In addition, the time profiles for degradation must be considered. Ideally, the material has to begin degrading in nature only after a certain period of time to ensure its usability under various conditions. Herein, we report that a tunable marine biodegradation profile and enhanced mechanical toughness can be achieved by embedding hydrophobic and water-responsive linkages into biodegradable polymers. Two types of boronic acid-based hydrolyzable adducts, namely, boroxine and boronic/boronate esters, were used as linkers to extend or cross-link short biodegradable polymer chains. The linkages increased the surface hydrophobicities of the polymers. This, together with the hydrolyzability of the linkages, effectively controlled the biodegradation profiles of the polymers in seawater and varied the lag times before the onset of biodegradation. Moreover, the introduction of the linkages enhanced the mechanical properties of the polymers. This study provides a general methodology that enables the adjustment of the biodegradation profiles and mechanical reliability of polymeric materials to meet the needs for various uses.