Reconfigurable and tunable EMNa/PCL/HNTs composites integrated with rapid shape-memory and repeatable self-healing properties

Abstract

Although tremendous advances in the preparation of smart materials, it remains a great challenge to integrate rapid shape-memory and repeatable self-healing properties into one material system. Herein, a composite with controllable shape memory and repeatable self-healing properties was fabricated by incorporating the halloysite nanotubes (HNTs) into polyethylene-sodium methacrylate salt (EMNa)/poly ε-caprolactone (PCL) blend via melt blending method. The dynamic cluster/de-cluster of ionic clusters in EMNa matrix endow the composite with favorable self-healing repeatability. In addition, the introduction of HNTs can not only maintain well shape memory properties, but also greatly enhancing the self-healing effect. Specifically, EMNa/PCL/HNTs-3.0 possesses a superior dual shape memory property as manifested by a 97.9% shape fixing ratio and 98.5% shape recovery ratio, which take only 8 s for recovering permanent shape. Furthermore, this self-healed composite still exhibits excellent reusability and endurance, and the shape fixity and shape recovery ratios are both above 95% after 15 shape memory cycles. More interestingly, the integration of ionomer, two independent crystallization domain, and HNTs enhanced physical cross-linked network can effectively provide EMNa/PCL/HNTs composites with triple shape memory and reconfigurable properties. This work provides a promising strategy for designing reconfigurable and tunable composites integrated with rapid shape-memory and repeatable self-healing properties, demonstrating its versatile application potential in biomedical and smart engineering materials fields.