Stress controllability in thermal and electrical conductivity is important for flexible piezoresistive devices. Due to the strength‐elasticity trade‐off, comprehensive investigation of stress‐controllable conduction in elastic high‐modulus polymers is challenging. Here presented is a 3D elastic graphene‐crosslinked carbon nanotube sponge/polyimide (Gw‐CNT/PI) nanocomposite. Graphene welding at the junction enables both phonon and electron transfer as well as avoids interfacial slippage during cyclic compression. The uniform Gw‐CNT/PI comprising a high‐modulus PI deposited on a porous templated network combines stress‐controllable thermal/electrical conductivity and cyclic elastic deformation. The uniform composites show different variation trends controlled by the porosity due to different phonon and electron conduction mechanisms. A relatively high k (3.24 W m−1 K−1, 1620% higher than PI) and suitable compressibility (16.5% under 1 MPa compression) enables the application of the composite in flexible elastic thermal interface conductors, which is further analyzed by finite element simulations. The interconnected network favors a high stress‐sensitive electrical conductivity (sensitivity, 973% at 9.6% strain). Thus, the Gw‐CNT/PI composite can be an important candidate material for piezoresistive sensors upon porosity optimization based on stress‐controllable thermal or electrical conductivity. The results provide insights toward controlling the stress‐induced thermal/electrical conductivities of 3D interconnected templated composite networks for piezoresistive conductors or sensors.

Hydrogel-based sensors have attracted significant attention owing to their promising applications in artificial intelligence. However, developing robust hydrogel conductors with customizable functionality and excellent sensor properties is challenging. In this...

Graphene‐reinforced polymer composites with high thermal conductivity show attractive prospects as thermal transfer materials in many applications such as intelligent robotic skin. However, for the most reported composites, precise control of the thermal conductivity is not easily achieved, and the improvement efficiency is usually low. To effectively control the 3D thermal conductivity of graphene‐reinforced polymer nanocomposites, a hyperelastic double‐continuous network of graphene and sponge is developed. The structure (orientation, density) and thermal conductivity (in‐plane, cross‐plane) of the resulting composites can be effectively controlled by adjusting the preparation and deformation parameters (unidirectional, multidirectional) of the network. Based on the experimental and theoretical simulation results, the thermal conduction mechanism is summarized as a two‐stage transmission of phonons. The in‐plane thermal conductivity increases from 0.175 to 1.68 W m−1 K−1 when the directional compression ratio increases from 0% to 95%, and the corresponding enhancement efficiency exceeds 300. The 3D thermal conductivity reaches a maximum of 2.19 W m−1 K−1 when the compression ratio is 70% in three directions, and the graphene content is 4.82 wt%. Moreover, the thermal conduction network can be largely prepared by power‐driven roller equipment, making the composite an ideal candidate for sensitive robotic skin for temperature detection.

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Optically actuated shape recovery materials receive much interest because of their great ability to control the creation of mechanical motion remotely and precisely. An infrared (IR) triggered actuator based on shape recovery was fabricated using polyurethane (TPU) incorporated by sulfonated reduced graphene oxide (SRGO)/sulfonated carbon nanotube (SCNT) hybrid nanofillers. Interconnected SRGO/SCNT hybrid nanofillers at a low weight loading of 1% dispersed in TPU showed good IR absorption and improved the crystallization of soft segments for a large shape deformation. The output force, energy density and recovery time of IR-triggered actuators were dependent on weight ratios of SRGO to SCNT (SRGO:SCNT). TPU nanocomposites filled by a hybrid nanofiller with SRGO:SCNT of 3:1 showed the maximum IR-actuated stress recovery of lifting a 107.6 g weight up 4.7 cm in 18 s. The stress recovery delivered a high energy density of 0.63 J/g and shape recovery force up to 1.2 MPa due to high thermal conductivity (1.473 W/mK) and Young's modulus of 23.4 MPa. Results indicate that a trade-off between the stiffness and efficient heat transfer controlled by synergistic effect between SRGO and SCNT is critical for high mechanical power output of IR-triggered actuators. IR-actuated shape recovery of SRGO/SCNT/TPU nanocomposites combining high energy density and output forces can be further developed for advanced optomechanical systems.