Self-Assembling and Morphology Changes of Noncovalently Connected Micelles in Aqueous Media

_{A series of amphiphilic random copolymers poly ( acrylic acid-co-styrene) (P(AA-co-St)) with different compositions were synthesized by free radical copolymerization. The copolymers were characterized by means of IR,GPC, DSC and ¹H NMR. The self-assembling of P(AA-co-St)s with hydrophilic macromolecule poly(vinylpyrrolidone) (PVP) was carryied out in aqueous media and the micellization was studied by means of DLS and TEM. The results of DLS showed that hydrokinetic radiuses of micelles rises with initial concentrations of P(AA-co-St)s and PVP, contents of AA , molecular weight of PVP ,separately. As the concentration of PVP is kept constant and that of P(AA-co-St)s is in the rang of 1.0-1.5mg/mL, AA content of P(AA-co-St)s and molecular weight of PVP have a significant effect on micelle size. Besides,several fators such as the velocity of dropping during the self-assembling,pH,the concentrations of salt (NaCl) have effect on micelle size. TEM studies demonstrated that about 40nm vesicles were formed when PVPk-90(1.0mg/mL) assembled with P(AA-co-St)(nAASt =1:3)(1.0mg/mL).As the anion surfactant SDS was added during the self-assembling,about 200nm shuttle aggregates were formed.When SDS was changed to cation surfactant CTAB,the morphology of micelles is rod with regular shape,about 200nm.}