The self-assembly behavior of poly(ethylene oxide)-b-polystyrene- b-poly(acrylic acid) (PEO-b-PS-b-PAA) triblock copolymers in solution is the focus of this thesis. The triblock copolymers were synthesized by atom transfer radical polymerization (ATRP). The compositions of the block copolymers were determined by 1H NMR. The synthesized block copolymers have relatively low polydispersity indexes (PDI < 1.3) as proved by GPC. The influence of several factors on the ATRP of styrene or t-BA, such as temperature, catalyst and polymerization time, was also explored. The effects of several parameters on the self-assembly behavior of this triblock copolymer were investigated, including the nature and composition of the common solvent, PAA block length, pH, water content, and initial copolymer concentration. Multiple morphologies, such as spheres, vesicles, lamellae and rods have been prepared by varying the above parameters. In particular, vesicles with either PEO or PAA outside have been successfully prepared in dioxane/water. These vesicles may serve as carriers for potential encapsulation applications. The average size and corona chain composition of the triblock copolymer vesicles can be controlled by varying factors such as the PAA block length and pH. The polymer chains may have different arrangements in the vesicle wall, resulting in different corona chain compositions. The vesicles with PAA outside are stable in water, while the vesicles with PEO outside tend to flocculate. Nevertheless, the sediment can be redispersed under vigorous stirring.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.98522 |
| Date | January 2005 |
| Creators | Wu, Qinghua, 1977- |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Chemistry.) |
| Rights | © Qinghua Wu, 2005 |
| Relation | alephsysno: 002494244, proquestno: AAIMR24829, Theses scanned by UMI/ProQuest. |
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