Preparation of non-spherical particles from amphiphilic block copolymers
Simple self-assembly techniques to fabricate non-spherical polymer particles, where surface composition and shape can be tuned through temperature and the choice of non-solvents was developed. A series of amphiphilic polystyrene-b-poly(2-ethyl-2-oxazoline) block copolymers were prepared and through solvent exchange techniques using varying non-solvent composition a range of non-spherical particles were formed. Faceted phase separated particles approximately 300 nm in diameter were obtained when self-assembled from tetrahydrofuran (THF) into water compared with unique large multivesicular particles of 1200 nm size being obtained when assembled from THF into ethanol (EtOH). A range of intermediate structures were also prepared from a three part solvent system THF/water/EtOH. These techniques present new tools to engineer the self-assembly of non-spherical polymer particles.