Synthesis, Characterization and Modeling of ABC Triblock Terpolymers: The Effect of Block Sequence

摘要

Four equimolar terpolymers comprising ten units from each of the monomers methoxy hexa(ethylene glycol) methacrylate (HEGMA), 2-(dimethylamino)ethyl methacrylate (DMAEMA) and methyl methacrylate (MMA) were prepared by group transfer polymerization (GTP), and characterized by gel permeation chromatography (GPC) and proton nuclear magnetic resonance (~1H NMR) spectroscopy to confirm size homogeneity and composition. These terpolymers were the three block sequence isomers, ABC, BAC and ACB, as well as the statistical isomer. Aqueous solutions of the terpolymers were characterized by dynamic light scattering and turbidimetry to determine the hydrodynamic sizes and cloud points. The results indicated micelle formation in the triblocks, and absence of micellization with the statistical terpolymer. In general, a strong dependence of the hydrodynamic size and cloud point on polymer architecture was observed. Monte Carlo simulations on non-aggregating isomeric terpolymers of similar structure also showed a strong dependence of the radius of gyration on polymer architecture.