Highly Stretchable and Self‐Healable Graphene‐Encapsulated Liquid Metal Composites for Multifunctional Applications

Liquid metal (LM)-based polymer composites generally face the challenges in the formation of connected networks at low contents and anti-leakage at high contents, due to the 0D spherical shape and intrinsic fluidity of LM. Herein, graphene nanosheets (GNS) is used to encapsulate LM droplets, and then both collaborate to form hybrid networks in supramolecular polyurethane-urea (PUU) matrix. In the hybrid networks, GNS not only acts as a bridge between LM droplets to enable the formation of efficient pathways, but also plays an important role in the encapsulation of LM to prevent its leakage. Specifically, only 2.0 vol% GNS addition enables the composite with a superior electrical conductivity of 548.1 S/m at 25 vol% GNS@LM content, and excellent anti-leakage behavior at 45 vol% GNS@LM content. In addition, the GNS@LM/PUU composite possesses high stretchability with a strain of 902.4% and good self-healing properties with high healing efficiency of electrical conductivity (96.0%) at 80 °C for 24 h. The GNS@LM/PUU composite also presents high potential as thermal management, shielding, and Joule heating material. This work provides a facile strategy for fabricating high performance LM-based composites, which holds great promise for multifunctional application in highly integrated electronics.