AB2 + A Type Copolymerization Approach for the Preparation of Thermosensitive PEGylated Hyperbranched Polymers

Saha, Animesh and Ramakrishnan, S (2008) AB2 + A Type Copolymerization Approach for the Preparation of Thermosensitive PEGylated Hyperbranched Polymers. In: Macromolecules, 41 (15). pp. 5658-5664.

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Abstract

Hyperbranched polyethers having poly(ethylene glycol) (PEG) segments at their molecular periphery were prepared by a simple procedure wherein an AB2 type monomer was melt-polycondensed with an A-type monomer, namely, heptaethylene glycol monomethyl ether. The presence of a large number of PEG units at the termini rendered a lower critical solution temperature (LCST) to these copolymers, above which they precipitated out of an aqueous solution. In an effort to understand the effect of various molecular structural parameters on their LCST, the length of the hydrophobic spacer segment within the hyperbranched core and the extent of PEGylation were varied. Additionally, linear analogues that incorporates pendant PEG segments were also prepared and comparison of their LCST with that of the hyperbranched analogue clearly revealed that hyperbranched topology leads to a substantial increase in the LCST, highlighting the importance of the peripheral placement of the PEG units.

Item Type:	Journal Article
Publication:	Macromolecules
Publisher:	American Chemical Society
Additional Information:	Copyright of this article belongs to American Chemical Society.
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	24 Feb 2010 06:27
Last Modified:	19 Sep 2010 05:55
URI:	http://eprints.iisc.ac.in/id/eprint/25851

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