A Healable Supramolecular Polymer Blend Based on Aromatic π−π Stacking and Hydrogen-Bonding Interactions
journal contributionposted on 01.09.2010, 00:00 by Stefano Burattini, Barnaby W. Greenland, Daniel Hermida Merino, Wengui Weng, Jonathan Seppala, Howard M. Colquhoun, Wayne Hayes, Michael E. Mackay, Ian W. Hamley, Stuart J. Rowan
An elastomeric, healable, supramolecular polymer blend comprising a chain-folding polyimide and a telechelic polyurethane with pyrenyl end groups is compatibilized by aromatic π−π stacking between the π-electron-deficient diimide groups and the π-electron-rich pyrenyl units. This interpolymer interaction is the key to forming a tough, healable, elastomeric material. Variable-temperature FTIR analysis of the bulk material also conclusively demonstrates the presence of hydrogen bonding, which complements the π−π stacking interactions. Variable-temperature SAXS analysis shows that the healable polymeric blend has a nanophase-separated morphology and that the X-ray contrast between the two types of domain increases with increasing temperature, a feature that is repeatable over several heating and cooling cycles. A fractured sample of this material reproducibly regains more than 95% of the tensile modulus, 91% of the elongation to break, and 77% of the modulus of toughness of the pristine material.