Clickable Poly(ethylene glycol)-Based Copolymers Using Azide-Alkyne Click Cycloaddition-Mediated Step-Growth Polymerization

Arslan M., Gok Ö. , Sanyal R., Sanyal A.

MACROMOLECULAR CHEMISTRY AND PHYSICS, vol.215, no.22, pp.2237-2247, 2014 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 215 Issue: 22
  • Publication Date: 2014
  • Doi Number: 10.1002/macp.201400210
  • Page Numbers: pp.2237-2247


The design, synthesis, and post-polymerization functionalization of linear poly(ethylene glycol) (PEG)-based polytriazole copolymers containing thiol-reactive maleimide functional groups as pendant side chains are described. A copper(I)-catalyzed Huisgen-type 1,3-dipolar cycloaddition reaction is utilized to prepare copolymers through a combination of diazide-and dialkyne-functionalized triethylene glycol derivatives, along with a dialkyne-functionalized furan-protected maleimide-containing monomer. After the polymerization, a microwave-assisted retro-Diels-Alder reaction is utilized to unmask the pendant maleimide groups by removal of the furan moieties. Post-polymerization modifications of these PEG-based copolymers containing the furan-protected maleimide group are accomplished using a photoinitiated radical thiol-ene reaction, whereas polymers containing the reactive maleimide group are functionalized using the Diels-Alder and nucleophilic thiol-ene reactions. The nucleophilic thiol-ene reaction is utilized to fabricate hydrogels by treatment of the maleimide-containing PEG polymers with dithiol-containing crosslinkers. Facile functionalization of thus-obtained hydrogels under mild conditions is demonstrated through the treatment of the residual maleimide groups within the hydrogel with a thiol-containing fluorescent dye.