Synthesis and Dilute Solution Properties of N-(2-Hydroxypropyl) methacrylamide-Based Copolymers

Abstract

Poly[N-(2-Hydroxypropyl)methacrylamide] (PHPMA) shows excellent biocompatibility and thus is expected to be used as a carrier in a drug delivery system. In this study, we investigated how the difference in the monomer structure influences the sequence in copolymers composed of HPMA and monomers (MA-ahNHNH-Boc and MA-NHNH-Boc); the size of MA-ah-NHNH-Boc is larger than that of MA-NHNH-Boc by the alkyl chain (CH₂)₅ spacer. Because the obtained copolymers showed a phase separation behavior upon heating,we also investigated this phase separation behavior by turbidimetry and the molecular dimension in dilute aqueous solution by small-angle X-ray scattering (SAXS). Consequently, we found that the difference between the monomers (MA-ah-NHNH-Boc or MA-NHNH-Boc) significantly influences the monomer sequence in copolymer chains, the cloud point temperature, and the chain dimension in aqueous solution.