Rational design of supramolecular conjugated polymers displaying unusual colorimetric stability upon thermal stress

The colorimetric stability upon thermal stress of a series of conjugated polymer supramolecules prepared from 10,12-docosadiyndioic acid (DCDDA)-derived diacetylene monomers has been explored. Polydiacetylenes obtained from DCDDA-bis-mBzA 3, containing m-carboxyphenylanilido groups at the both ends of the monomer, were observed to be highly colorimetrically stable upon thermal stimulation. The blue color of a solution containing these polydiacetylene vesicles remains unchanged even when the vesicles were subjected to boiling water. The unusual colorimetric stability is further demonstrated by the observation that blue color persists until vesicles in ethylene glycol are heated to 140 °C. The nature of this unusual thermal stability was elucidated by using polydiacetylene supramolecules, prepared from analogs of DCDDA-bis-mBzA 3. The presence of internal amide groups as well as aromatic interactions was found to be essential for the high colorimetric stability of the polydiacetylene supramolecules.