Search

The hydrodynamic volume for a series of hyperbranched polymers was studied to determine the volume change in a variety of solvents. The chemically different interior core and branching units were found to readily expand and contract by a factor of 2 creating large or small free volume, respectively. Furthermore, a solvent that maximally swells the polymer created a viscosimetric (hydrodynamic) radius which changed linearly with molecular mass. This is contrary to what is expected for dendrimers where the radius has been shown to scale with ln(M). A model was developed to account for the effect of molecular mass polydispersity on the intrinsic viscosity (viscosimetric volume), since hyperbranched polymers are polydisperse in nature, and it was found that this did not affect the observation. Solvents that contracted the hyperbranched polymers showed a complicated hydrodynamic radius scaling with mass. It was generally concluded that these polymers readily change volume with solvent effects important in infl...

A supramolecular elastomer comprising a blend of a pyrenyl-tweezer-ended polyamide intercalating with a chain-folding polyimide shows near-quantitative thermal healability. It also exhibits greatly enhanced toughness relative to an analogous system in which the polyamide end-groups are simple pyrenyl residues, reflecting the increased association constant between the two complementary binding motifs.