Cooperative end-to-end and lateral hydrogen-bonding motifs in supramolecular thermoplastic elastomers

The effect of combining very strong end-to-end association via ureidopyrimidinone (UPy) quadruple hydrogen bonding and directional aggregation via the urea (U) and urethane (T) hydrogen bonding motifs to give supramolecular thermoplastic elastomers was investigated. It was shown that the presence of laterally aggregating urea groups in UPy-based supramolecular polymer with both lateral and end-to-end functionalities, UPy-U-PEB-U-UPy, gives rise to 1-D aggregation of end groups in long fibers. This material showed noticeable elastic properties below the melting point due to a combination of supramolecular polymerization and nanophase segregation. It was found that mechanical properties of UPy-U-PEB-U-UPy are more enhanced due to the more difficult chain pullout from fibrils that that of the fibers which combine end-on and lateral interactions.