Room-temperature self-healing, high ductility, recyclable polyurethane elastomer fabricated via asymmetric dynamic hard segments strategy combined with self-cleaning function application

It is challenging to prepare room temperature self-healing materials that balance self-healing and mechanical properties. In this study, we introduces a concept of “asymmetric dynamic hard segments” to balance mechanical strength and self-healing properties while ensuring high ductility and recyclability. The introduction of asymmetric dynamic hard segments allows polymer chains to form an amorphous structure and high mobility and enables the dissociation and rapid recombination of multiphase hydrogen bonds. Based on this feature, a simple two-step polycondensation reaction was reported to synthesise a room-temperature-self-healing polyurethane elastomer (PPG-IH-IPDA) with good mechanical strength, good toughness, high ductility and excellent recyclability. The experimental results showed that room-temperature self-healing completely eliminated scratches on PPG-IH-IPDA, and the mechanical properties of the elastomer were fully restored. With the advantageous characteristics of PPG-IH-IPDA, the perfect combination of self-healing and self-cleaning functions leads to the preparation of a superhydrophobic composite material (SHN-SiO2/PPG-IH-IPDA) that shows a contact angle greater than 150°, which enables surface damage self-healing at room temperature. The proposed combination of self-healing and self-cleaning properties provides substantial guidance for the development of versatile materials.