Multifunctional poly[N-(2-hydroxypropyl)methacrylamide] copolymers via post-polymerization modification and sequential thiol–ene chemistry
Nora Francini, Laura Purdie, Cameron Alexander, Giuseppe Mantovani and Sebastian G. Spain*; Macromolecules, 2015, 48, 2857-2863. [DOI]
Poly[N-(2-hydroxypropyl)methacrylamide] is a promising candidate material for biomedical applications. However, synthesis of functional pHPMA via compolymerization results can lead to variations in monomer composition, molar mass, and dispersity making comparison difficult. Postpolymerization modification routes, most commonly aminolysis of poly[active ester methacrylates], have alleviated some of these problems, but ester hydrolysis can lead to other problems. Here we report the synthesis of multifunctional pHPMA via a simple two-step derivatization of pHPMA homopolymer using readily available standard reagents and atom-efficient procedures. First, treatment with allyl isocyanate yields the corresponding carbamate with predictable incorporation of side-chain functionality. Allyl-pHPMA can then be derivatized further via radical thiol–ene reactions to generate pHPMA with multiple diverse functionalities but without adverse effects on the molecular weight and dispersity of the polymer. The applicability of the method to production of biologically relevant materials is demonstrated by cytocompatibility and cell labeling experiments with easily prepared ligand-functionalized pHPMA in the HCT 116 model cell line.