RAFT Synthesis of a Thermally Responsive ABC Triblock Copolymer Incorporating N-Acryloxysuccinimide for Facile In Situ Formation of Shell Cross-Linked Micelles In Aqueous Media
Document Type
Article
Publication Date
1-10-2006
Department
Polymers and High Performance Materials
Abstract
A poly(ethylene oxide) (PEO)-based macromolecular chain transfer agent (macro-CTA) was employed to demonstrate the controlled polymerization of N,N-dii-nethylacrylamide (DMA) in anhydrous 1,4-dioxane at 70 degrees C using reversible addition-fragmentation chain transfer polymerization. This macro-CTA was then used to mediate the statistical copolymerization of DMA and the reactive monomer N-acryloxysuccinimide (NAS), forming a diblock copolymer of PEO-b-(DMA-s-NAS). Subsequent chain extension with N-isopropylacrylamide (NIPAM) yielded a PEO-b-(DMA-s-NAS)-b-NIPAM thermally responsive triblock copolymer. In aqueous solution at room temperature the triblock copolymer chains exist as unimers but form micelles when the solution temperature is raised above the lower critical solution temperature (LCST) of the NIPAM block. The hydrodynamic dimensions and micellization temperatures depend on the length of the NIPAM block. Incorporation of the NAS units into the triblock copolymer allows for facile formation of uniform shell cross-linked micelles by reaction with difunctional primary amines in aqueous media. These shell cross-linked micelles swell when the solution temperature is lower than the LCST of the NIPAM block.
Publication Title
Macromolecules
Volume
39
Issue
1
First Page
81
Last Page
89
Recommended Citation
Li, Y.,
Lokitz, B. S.,
McCormick, C. L.
(2006). RAFT Synthesis of a Thermally Responsive ABC Triblock Copolymer Incorporating N-Acryloxysuccinimide for Facile In Situ Formation of Shell Cross-Linked Micelles In Aqueous Media. Macromolecules, 39(1), 81-89.
Available at: https://aquila.usm.edu/fac_pubs/2506