New zwitterionic polyurethanes containing pendant carboxyl-pyridinium with shape memory, shape reconfiguration, and self-healing properties

Abstract

In this paper, novel zwitterionic polyurethane containing pendant carboxyl-pyridinium were successfully prepared with N,N-bis(2-hydroxyethyl) isonicotinamide (BINA) and hexamethylene diisocyanate (HDI), followed by zwitterionization with 4-bromobutyric acid. The structure, morphology and properties, including shape memory, shape reconfiguration and self-healing properties, were carefully investigated. The obtained results showed that introduction of zwitterionic units reduced glass transition temperature. The shape recovery increased with increasing carboxyl zwitterion content. Finally, good shape memory properties with 99% shape memory and 99% shape recovery was achieved. Additionally, the carboxyl-pyridinium zwitterionic polyurethane had good shape reconfiguration properties, and new permanent shapes could be reconfigured easily upon heating. Moreover, the carboxyl-pyridinium zwitterionic polyurethanes possessed moisture-induced self-healing properties, where its complex structure was self-repaired in a humidity-rich environment after inevitable damage. This study opens a new door to intelligent zwitterionic polymers, which is highly significance in the field of smart biomedical.