Thermo-responsive microphase separated supramolecular polyurethanes

Abstract

The ability to generate very stable assemblies via non-covalent interactions has enabled materials to be constructed that were not feasible via ‘traditional’ covalent bond formation processes. A series of low molecular mass bisurethane and bisurea polymers have been developed that form stable self-assembled networks through hydrogen bonding interactions. Thermo-responsive polymers were generated by end-capping poly(ethylene-co-butylene) or polybutadiene chains with the bisurethane or bisurea motif. Microphase separation is observed via TEM and small-angle X-ray scattering (SAXS) for the modified pseudo polymers and significant differences in the temperature dependence of microphase separation are analysed via SAXS. The importance of the polarity of the end groups is manifested in distinct temperature-dependent microphase separation behaviour. Information on the local hydrogen bonding structure is provided by wide-angle X-ray scattering and variable temperature FTIR.