In order to impart temperature-responsiveness within a physiologically-relevant context to poly(ethylene glycol)-based biomaterials, a new versatile platform was developed to precisely tune the lower critical solution temperature (LCST) of poly(ethylene glycol-co-ally glycidyl ether) (PEG-co-PAGE) copolymers. Facile thiol-ene functionalization of the pendant allyl groups with n-alkane thiols allows for the accurate adjustment of the LCST by varying the length of the n-alkane chain. Increasing the number of n-alkane carbons from zero (i.e. unreacted AGE units) to eight (i.e. functionalization with 1-octanethiol) results in a decrease of LCST from 70 °C to 20 °C. In contrast to copolymerization of ethylene oxide with hydrophobic glycidyl ether monomers, this post-polymerization functionalization approach gives access to temperature-sensitive PEG-derivatives that only differ in their cloud-point temperature but not in their degree of polymerization, polydispersity and endgroup functionality. Therefore, by controlling the copolymer architecture, it represents a flexible synthetic tool to such higher order macromolecular assemblies as temperature-sensitive micelles and hydrogels.

Versatile platform to temperature-responsive PEG-based materials: Facile post-polymerization functionalization of PEO-co-PAGE with n-alkane thiols

249th National Meeting (2015)

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