Self-assembly of well-defined triblock copolymers based on poly(lactic acid) and poly(oligo(ethylene glycol) methyl ether methacrylate) prepared by ATRP

Abstract

Self-assembly of a series of amphiphilic poly(oligo(ethylene glycol) methyl ether methacrylate)-block-poly(lactic acid)-block-poly(oligo(ethylene glycol) methyl ether methacrylate) (P(OEGMA)-b-PLLA-b-P(OEGMA)) copolymers was investigated. The copolymers were synthesized by a combination of ring-opening polymerization (ROP) of L-lactide and atom transfer radical polymerization (ATRP) of oligo ethylene glycol methyl ether methacrylate (OEGMA). The resulting brush-like triblock copolymers were characterized by ¹H NMR and size exclusion chromatography. Self-assembly behavior of the copolymers in deionized water was investigated by fluorescence spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM). The critical aggregation concentration ranged from 50 to 160 mg L⁻¹ depending on the composition. The diameter of the nanoparticles (NPs) was determined by DLS and TEM. Images showed that these nano-sized objects displayed spherical and worm-like morphology with a length increasing with the hydrophilic content. Preliminary studies of drug loading and drug release with a water-insoluble model drug, namely curcumin, showed that these NPs are potential candidates for drug delivery carriers.