Self-assembly of Polystyrene-b-poly(4-vinylpyridine) in Deoxycholic acid
Date Issued
2010
Date
2010
Author(s)
Yu, Cheng-Hao
Abstract
Amphiphilic block copolymers in selective solvents self-assemble into micro/nano-scaled structures, such as spherical micelles, cylindrical micelles and vesicles, in which solvent-philic blocks tend to contact with solvents and shield solvent-phobic blocks from the solvents. The formation conditions and mechanisms of such structures have been widely studied.
Different from the conventional micellization in liquid systems, ,in this study we found that block copolymer poly(styrene-block-4-vinylpyridine) (PS-b-P4VP) can self-assemble in melted deoxycholic acid (DCA) at high temperature and more interestingly, the structures can be retained in “solid state” after cooled down to room temperature. Transmission electron microscopy (TEM) was used to probe the structure and we found that different self-assembled structures, including spherical micelles, cylindrical micelles and vesicles can be obtained by varying the length of block copolymers and the morphologies depend on annealing temperature and annealing time. We will discuss the mechanisms of the micellization in this thesis.
Since these nano-structures can be retained in solid state, we tried to extract the nano-structures by removing deoxycholic acid using appropriate solvents. These extracted structures, especially the vesicles, are potential for applications, such as drug delivery.
Subjects
micelles
vesicles
self-assembly
amphiphilic block copolymers
solid selective solvent
deoxycholic acid
Type
thesis
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