Grafting-through ROMP for Gels with Tailorable Moduli and Crosslink Densities

A new type of chemically-crosslinked polymeric network was synthesized by grafting-through ring-opening metathesis polymerization (gt-ROMP) using well-defined norbornene functionalized macrocrosslinkers. These macromolecular grafted-through networks uniquely possessed two molecular-level dials for tuning network microstructure and mechanical properties. In particular, both facets of the crosslink density, i.e. network junction functionality and molecular weight between crosslinks, could be independently manipulated by varying the macrocrosslinker degree of polymerization or the gt-ROMP degree of polymerization, providing shear storage moduli ranging over an order of magnitude.