Novel Sulfur‐Containing Carbon Nanotubes with Graphene Nanoflaps for Stretchable Sensing, Joule Heating, and Electro‐Thermal Actuating

Abstract Stretchable conductors based on nanopercolation networks have garnered great attention for versatile applications. Carbon nanotubes (CNTs) are well‐suited for creating high‐efficiency nanopercolation networks. However, the weak interfacial shear strength (IFSS) between CNTs and elastomer hardly dissipates the deformation energy and thus deteriorates the conductive network. Herein, a novel sulfur‐containing CNTs attached with abundant graphene nanoflaps using a two‐step sulfidation strategy are developed. The sulfur functionality creates a strong interfacial interaction with the elastomer polymer, while the graphene nanoflaps provide an enhanced, intertwined shear interface with elastomer that is capable of efficiently dissipating the deformation energy. As a result, the optimized nanocomposite significantly improves the IFSS between nanofiller and elastomer, displaying remarkable conductive robustness (Δ R / R 0 ≈1.8 under 200%), superior stretchability (> 450%), and excellent mechanical durability (≈30 000 cycles). Moreover, the nanocomposite demonstrates excellent Joule heating efficiency (≈150 °C in 12 V), stretchable heating conversion (≈200%), and long‐term stability (> 24 h). To illustrate its capabilities, the nanocomposite is used to track human physiological signals and perform electric‐thermal actuating as a set of soft tongs. It is believed that this innovative approach will provide value for the development of wearable/stretchable devices, as well as human‐machine interaction, and bio‐robotics in the future.