Phase structure and transition behavior of zwitterionic polyurethane containing sulfobetaine

Zwitterionic polyurethane has been intensively studied due to their strong hydration ability and molecular interaction, with the most of reports focused on the post-polymerization functionalization. Herein, a series of block zwitterionic polyurethanes (SBZPUs) containing sulfobetaine-diol (SB-diol) are synthesized, and their crystallization, phase structure, and transition behavior are fully characterized with NMR, FT-IR, DSC, SAXS, WAXS, and AFM, to ascertain the effect of the ionic interactions. It is found that the introduction of zwitterionic SB-diol disrupts the hydrogen bonding of hard segments, while improves the crystallization of soft segment and micro-phase separation of SBZPUs due to the strong ionic interactions. The physical and mechanical properties of SBZPUs could be adjusted by varying the SB-diol amount, and the transition point could be tuned to around human body temperature. In combination with the excellent cytocompatibility, SBZPUs show a promising potential in applications of biomedical materials.