Additives induced morphological transition of molecular assemblies from PS-b-PGEA in aqueous solutions

Abstract

Polystyrene-block-poly[2-(β-D-glucosyloxy)ethyl acrylate] (PS-b-PGEA) can form a variety of molecular assemblies in aqueous media when initially dissolved in water-soluble organic solvents, such as N,N-dimethylformamide (DMF), THF, etc. The morphologies of these molecular assemblies are affected by the copolymer composition, the nature of the solvent and the initial copolymer concentration. Thus, morphological transformations can be realized by varying the above parameters. In this paper, the effects of additives, such as glucose, HCl, Concanavalin A (Con A), and CaCl₂, on the aggregates of PS-b-PGEA in dilute aqueous solutions have been investigated. PS₇₇-b-PGEA₆ yielded predominantly spheres in water when initially dissolved in DMF at a concentration of 0.1–0.2 wt %. A transformation of the morphology to bilayer structures upon addition of different amounts of glucose, HCl, Con A or CaCl₂ was observed. The morphological transitions can be ascribed to the decrease of the repulsive interactions among corona-forming blocks.