Unimolecular Micelles and Reverse Micelles Based on Hyperbranched Polyethersa-Comparative Study of A$B_{^2}$+ A-R and $A_{^2}$ + $B_{^3}$ + A-R Type Strategies

Saha, Animesh and Ramakrishnan, S (2009) Unimolecular Micelles and Reverse Micelles Based on Hyperbranched Polyethersa-Comparative Study of A$B_{^2}$+ A-R and $A_{^2}$ + $B_{^3}$ + A-R Type Strategies. In: Journal of Polymer Science Part A-Polymer Chemistry, 47 (01). pp. 80-91.

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Abstract

Core-shell type hyperbranched polymers that are capable of forming unimolecular micelles and reverse micelles in aqueous and hydrocarbon medium, respectively, were synthesized via two approaches, namely AB(2) + A-R and A(2) + B-3 + A-R type copolymerizations. In case of micelle-forming polymers, an AB(2) monomer carrying a decamethylene spacer was used along with heptaethylene glycol monomethyl ether (HPEG) as the A-R type comonomer. One the other hand, for the preparation of reverse micelle-forming polymers, an AB2 monomer containing an oligo(oxyethylene) spacer was used along with cetyl alcohol as the A-R type comonomer. The former was readily soluble in water while the latter was soluble in hydrocarbon solvents like hexane. NMR spectral studies confirmed that both the approaches generated highly branched structures wherein about 65-70% of the terminal B groups were capped by the A-R comonomer. Dye-uptake measurements revealed that the polymers prepared via the AB(2) + A-R approach exhibited a significantly larger uptake compared with those prepared via the A(2) + B-3 + A-R approach. This suggests that the AB(2) + A-R approach generates hyperbranched polymers with better defined core-shell topology when compared with polymers prepared via the A(2) + B-3 + A-R approach, which is in accordance with previous studies that suggest that A(2) + B-3 approach yields polymers with significantly lower branching levels and consequently less compact structures.

Item Type:	Journal Article
Publication:	Journal of Polymer Science Part A-Polymer Chemistry
Publisher:	Wiley
Additional Information:	Copyright of this article belongs to Wiley.
Keywords:	core-shell polymers; hyperbranched; unimolecular micelles
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	20 Nov 2009 10:08
Last Modified:	19 Sep 2010 05:24
URI:	http://eprints.iisc.ac.in/id/eprint/18697

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