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.