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  • Responsive micellar films of amphiphilic block copolymer micelles: control on micelle opening and closing.

Responsive micellar films of amphiphilic block copolymer micelles: control on micelle opening and closing.

Langmuir : the ACS journal of surfaces and colloids (2010-04-15)
Zhiquan Chen, Changcheng He, Fengbin Li, Ling Tong, Xingzhi Liao, Yong Wang
ABSTRACT

We reported the deliberate control on the micelle opening and closing of amphiphilic polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) micellar films by exposing them to selective solvents. We first treated the micellar films with polar solvents including ethanol and water (pH = 4, 8, and 12) that have different affinities to P2VP. We observed opening of the micelles in all the cases. Both the size of opened pores and the opening rate are dependent on the solvency of different solvents for P2VP. We then explored the closing behavior of the opened micelles using solvents having different affinities to PS. We found that the opened micelles were recovered to their initial closed micelle forms. The recovery was accompanied by a slow micelle disassociation process which gradually reduced the micelle size. The rates of the micelle closing and disassociation are also dependent on the solvency of different solvents for PS.

MATERIALS
Product Number
Brand
Product Description

Supelco
Poly(2-vinylpyridine), analytical standard, average Mw 159,000 (Typical), average Mn 152,000 (Typical)
Supelco
Poly(2-vinylpyridine), analytical standard, average Mw 37,500 (Typical), average Mn 35,000 (Typical)