Evaporation-induced Self-assembly of Polystyrene-b-poly (acrylic acid) Nanomicelles on the Silicon Wafer

Solvent evaporation-induced self-assembly was adopted to prepare regular aggregates. This process included two steps. Firstly, the amphiphilic polystyrene-block-poly (acrylic acid) (PS-b-PAA) micelles which were synthesized via atom transfer radical polymerization (ATRP) self-assembled into cubic nanomicelles in THF/water mixed solution. Secondly, the nanomicelle solution with a small quantity of tetrahydrofuran (THF) or N,N-dimethylformamide (DMF), which plays the role of additive, was dropped on the silicon wafer, and the method of solvent evaporation-induced self-assembly was used to aggregate the nanomicelle. Depending on the kind of additive and temperature, the morphology of the orderly aggregate was varied from flower-like to rodlike. Moreover, a possible mechanism was proposed.