Polyurethane/silver Nanowire Composites with Diels-Alder Structure for Self-Healing and Thermal Conduction Abilities

To meet the non-removable application scenarios of most integrated electronics, the development of polymerbased packaging materials possessing superior thermal conductivity and self-healing characteristics simultaneously is necessary. However, on account of the complexity of composite structure and composition, its self-heal remains a formidable challenge. Herein, we have designed a self-healing and thermally conductive bi-functional polyurethane composites with Diels-Alder structure (PUDA) and silver nanowires (AgNWs). The hydrogenbonding network at the interface of AgNWs and PUDA facilitated the dispersion of AgNWs in the matrix, which endows the composites with desirable thermal conductivity. Incorporating 3, 6, 9, 12, and 15 wt% of AgNWs into PUDA leads to increases in thermal conductivity of 33%, 104%, 154%, 321%, and 371%, respectively. In particular, the novel composites incorporated 12 wt% AgNWs exhibited the most efficient balance between self-healing efficiency and thermal conductivity performance. The thermal conductivity of PUDA/ AgNWs with 12% of AgNWs content is 1.01 W/mK, which is 4.8 times that of PUDA (0.21 W/mK). After two reconstitution cycles, the thermal conductivity of PUDA/AgNWs-12 was restored to 85%. This study demonstrates the successful preparation of composites possessing both desirable thermal conductivity and self-healing capabilities, rendering them suitable for use as thermal interface materials in thermal management systems and flexible electronics applications.