Evaporation-Induced Aggregation of Polystyrene-block-poly(acrylic acid) Micelles to Microcubic Particles

An evaporation-induced method for aggregation of polystyrene- block -poly(acrylic acid) (PS- b -PAA) micelles to unusual polymeric microcubic particles is reported. PS- b -PAA self-assembles into spherical nanomicelles in the block-selective solvent water. After addition of butanone, 1-propanol, acetic acid, N, N -dimethylformamide (DMF), or n -butylamine, evaporation of the solvent mixture induces aggregation of the nanomicelles into microcubic particles on the substrate a glass slide. The concentration of the additive, temperature, and substrate affect the morphology of the aggregation of the nanomicelles. Vaporizing the additive/water mixture at 120 °C results in the formation of highly symmetrical microcubic particles on a glass slide. The size of microcubic particles is in range from 200 × 200 × 200 nm 3 to 600 × 600 × 600 nm 3 . Microcubic particles can also form on a silicon and gold wafer with a size similar to that of those formed on a glass slide. The morphology of the microcubic particles almost remains unchanged at temperatures lower than 150 °C, while it is destroyed above 200 °C.