Development of supramolecular shape-memory polyurethanes based on Cu(II)–pyridine coordination interactions

Shape-memory polymers with supramolecular switch have received increasing attention. This study reports the synthesis and characterization of supramolecular shape-memory polyurethane based on Cu(II)–pyridine coordination, obtained by mixing pyridine containing polyurethane with CuCl2. The results show that there are strong metal–ligand coordination interactions formed between Cu(II) and the pyridine ring in a series of CuCl2-doped polyurethane samples. The Cu(II)–pyridine coordination plays a crucial role in the enhanced physical netpoints for outstanding shape-memory properties. Indeed, the so-synthesized CuCl2-doped polyurethane exhibits not only a rapid tensile shape recovery but also excellent crimp shape recovery. The CuCl2-doped polyurethane containing suitable metal–ligand coordination interactions shows more than 99% shape fixation and more than 95% shape recovery. Our findings promote further applications of shape-memory polymers in multiple engineering fields.