Multiple morphologies of molecular assemblies formed by polystyrene-block-poly[2-(β-D-glucopyranosyloxy)ethyl acrylate] in water

Abstract

A variety of molecular assemblies have been prepared from a new kind of amphiphilic diblock copolymer, polystyrene-block-poly[2-(β-D-glucopoyranosyloxy)ethyl acrylate] (PSt-b-PGEA). The morphologies include spheres, vesicles, tubules, porous spheres and large compound vesicles. These molecular assemblies are similar in morphology to the so-called ‘‘crew-cut ’’ aggregates that have been systematically studied by Eisenberg’s group and were prepared in the same manner. The preparation of such molecular assemblies was carried out by first dissolving the copolymer in a common solvent, followed by addition of water to freeze the polystyrene block. The solvents used in this report were N,N-dimethylformamide (DMF), tetrahydrofuran (THF), dioxane and their mixtures. It has been observed that by changing the solvent, or the solvent mixture, different morphologies can be obtained from a single copolymer, and the transformation of these morphologies can be easily adjusted by changing the composition of the solvent mixture. One typical example is the morphological transitions between tubules and vesicles of PSt₇₇-b-PGEA₆, which is initially dissolved in mixed THF–DMF solvent. These molecular assemblies contain a high density of glucose moieties on the surface, therefore, they may find applications as cellular-specific drug delivery systems or be used as building blocks for highly ordered supramolecular architectures.