title: New ground for organic catalysis: a ring-opening polymerization approach to hydrogels.
abstract: Herein, we describe an organocatalytic living polymerization approach to network and subsequent hydrogel formation. Cyclic carbonate-functionalized macromolecules were ring-opened using an alcoholic initiator in the presence of an organic catalyst, amidine 1,8-diazabicyclo[5.4.0]undec-7-ene. A model reaction for the cross-linking identified monomer concentration-dependent reaction regimes, and enhanced kinetic control was demonstrated by introducing a co-monomer, trimethylene carbonate. The addition of the co-monomer facilitated near-quantitative conversion of monomer to polymer (>96%). Resulting poly(ethylene glycol) networks swell significantly in water, and an open co-continuous (water-gel) porous structure was observed by scanning electron microscopy. The organocatalytic ring-opening polymerization of cyclic carbonate functional macromonomers using alcoholic initiators provides a simple, efficient, and versatile approach to hydrogel networks.
authors.affiliation: IBM Almaden Research Center, 650 Harry Road, San Jose, CA 95120, USA.
authors.forename: Fredrik
authors.initials: F
authors.lastname: Nederberg
authors.forename: Vivian
authors.initials: V
authors.lastname: Trang
authors.forename: Russell C
authors.initials: RC
authors.lastname: Pratt
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Mason
authors.forename: Curtis W
authors.initials: CW
authors.lastname: Frank
authors.forename: Robert M
authors.initials: RM
authors.lastname: Waymouth
authors.forename: James L
authors.initials: JL
authors.lastname: Hedrick
mesh_terms: D002254:Carbonates / Q000737:chemistry; D002384:Catalysis; D003432:Cross-Linking Reagents / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry*; D047028:Macrocyclic Compounds / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008855:Microscopy, Electron, Scanning; D015394:Molecular Structure; D011092:Polyethylene Glycols / Q000737:chemistry*
chemical_list: D002254:Carbonates; D003432:Cross-Linking Reagents; D020100:Hydrogels; D047028:Macrocyclic Compounds; D011092:Polyethylene Glycols