New PEG-based hydrogel materials have been synthesized by Click chemistry and shown to result in well-defined networks having significantly improved mechanical properties; the selectivity of the azide/acetylene coupling reaction also allows for the incorporation of various additives and functional groups leading to chemical tailoring of the hydrogels.

A series of titanium bis(phenoxyketimine) olefin polymerization catalysts were synthesized and screened for propylene polymerization. The phenoxyketimine ligands contain pentafluorophenyl N-aryl groups and ortho-phenol substituents of varying size. Catalysts with ortho-phenol substituents of intermediate size produce living, substantially isotactic polypropylene. The living nature of these catalyst systems is demonstrated through the synthesis of block copolymers with narrow molecular weight distributions.

New titanium catalysts with ancillary, non-fluorinated phenoxyketimine ligands have been synthesized and found to be active for living ethylene polymerization.

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.