Degradable Polymer Synthesis via Photopolymerization

Light-mediated polymerization has emerged as a powerful tool in the synthesis of advanced materials. The spatial and temporal control imparted by light makes it an appealing external source of energy for initiation. While much of the work previously reported on photocontrolled and photoinitiated systems has focused on the radical or cationic polymerization of vinyl monomers, expanding the scope to the synthesis of degradable polymers like polyesters and polypeptides could lead to materials that are both biocompatible and degradable. The polymerization of <i>N</i>-carboxyanhydrides (NCAs) affords access to a vast array of synthetic polypeptides with tunable molecular weights, functionalities, and architectures. The use of light to achieve spatiotemporal control over these polymerizations could expand their applicability to a variety of areas, including 3D printing and photolithography. Moreover, modern advances in photopolymerization can be extended to other classes of monomers that lead to degradable polymers, including radical polymerization of cyclic ketene acetals (CKAs). By copolymerizing CKAs with electron-deficient monomers, it is possible to achieve copolymers with a uniform distribution of degradable ester linkages along their backbone.