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The synthesis and self-assembly of ABA amphiphilic block copolymers containing styrene and oligo(ethylene glycol) methyl ether methacrylate in dilute aqueous solutions: Elevated cloud point temperatures for thermoresponsive micelles

Holder, Simon J., Durand, Geraldine G, Yeoh, Chert-Tsun, Illi, Elodie, Hardy, Nicholas J, Richardson, Tim H (2008) The synthesis and self-assembly of ABA amphiphilic block copolymers containing styrene and oligo(ethylene glycol) methyl ether methacrylate in dilute aqueous solutions: Elevated cloud point temperatures for thermoresponsive micelles. Journal of Polymer Science Part A: Polymer Chemistry, 46 (23). pp. 7739-7756. ISSN 1099-0518. (doi:10.1002/pola.23077) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Official URL
http://dx.doi.org/10.1002/pola.23077

Abstract

A series of ABA amphiphilic triblock copolymers possessing polystyrene (PS) central hydrophobic blocks, one group with “short” PS blocks (DP = 54–86) and one with “long” PS blocks (DP = 183–204) were synthesized by atom transfer radical polymerization. The outer hydrophilic blocks were various lengths of poly(oligoethylene glycol methyl ether) methacrylate, a comb-like polymer. The critical aggregation concentrations were recorded for certain block copolymer samples and were found to be in the range circa 10?9 mol L?1 for short PS blocks and circa 10?12 mol L?1 for long PS blocks. Dilute aqueous solutions were analyzed by transmission electron microscopy (TEM) and demonstrated that the short PS block copolymers formed spherical micelles and the long PS block copolymers formed predominantly spherical micelles with smaller proportions of cylindrical and Y-branched cylindrical micelles. Dynamic light scattering analysis results agreed with the TEM observations demonstrating variations in micelle size with PS and POEGMA chain length: the hydrodynamic diameters (DH) of the shorter PS block copolymer micelles increased with increasing POEGMA block lengths while maintaining similar PS micellar core diameters (DC); in contrast the values of DH and DC for the longer PS block copolymer micelles decreased. Surface-pressure isotherms were recorded for two of the samples and these indicated close packing of a short PS block copolymer at the air–water interface. The aggregate solutions were demonstrated to be stable over a 38-day period with no change in aggregate size or noticeable precipitation. The cloud point temperatures of certain block copolymer aggregate solutions were measured and found to be in the range 76–93 °C; significantly these were ?11 °C higher in temperature than those of POEGMA homopolymer samples with similar chain lengths. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7739–7756, 2008

Item Type: Article
DOI/Identification number: 10.1002/pola.23077
Additional information: number of additional authors: 5;
Uncontrolled keywords: amphiphilic block copolymer; atom transfer radical polymerization (ATRP); block copolymers; cloud point; colloids; micelles; oligo(ethylene glycol) methyl ether methacrylate; self-assembly; stimuli-sensitive polymers; thermoresponsive
Subjects: Q Science
Q Science > QC Physics
Divisions: Faculties > Sciences > School of Physical Sciences
Depositing User: Stewart Brownrigg
Date Deposited: 07 Mar 2014 00:05 UTC
Last Modified: 01 Aug 2019 10:37 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/40479 (The current URI for this page, for reference purposes)
Holder, Simon J.: https://orcid.org/0000-0001-8977-9257
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