Aggregate Morphologies of PS-b-PEO-b-PS Copolymer in Mixed Solvents

Taking the aggregate structures of polystyrene-b-poly (ethylene oxide)-b-polystyrene (PS-b-PEO-b-PS) block copolymer in tetrahydrofuran (THF) and N, N-Dimethylformamide (DMF) solvents as the starting point, further experiments were carried out to change the aggregate morphologies by adding PEO selective solvent, water, into the primarily solutions. Primarily, the microcrystal "platelets" and "spherical" aggregates were obtained in THF and DMF, respectively. After water being added into the aggregated system in THF, the macrophase separation occurred in the solution, and the further adding of water led to the formation of large compound micelles (LCMs). Nevertheless, the adding of water into spherical aggregates in DMF only leaded the decrease of aggregate size.