3D-printable and multifunctional conductive nanocomposite with tunable mechanics inspired by sesame candy

Viscoelastic Silly Putty-like conductive nanocomposites have recently received considerable attention in wearable electronics, soft robotics, energy storage, electromagnetic interference (EMI) shielding, and triboelectric nanogenerators (TENGs) due to their unique electrical and mechanical properties. However, great challenges remain for conventional Silly Putty-like materials in terms of electrical conductivity and printability, which seriously hindered their wide applications. Herein, inspired by sesame candy, a viscoelastic Silly Putty-like conductive nanocomposite (LPPC) composed of LAPONITE® XLG/carbon nanotubes (CNTs)/poly(3,4ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS)/poly(ethylene oxide) (PEO) is fabricated based on electrostatic/coordination interactions and hydrogen bonds. The viscoelasticity of LPPC can be modulated as required by adjusting the water content. Owing to the typical shear-thinning behavior, LPPC possesses 3D printing feasibility. Taking advantage of its high electrical conductivity, good moldability, printability, and recyclability, multiple applications of LPPC are explored by employing different processing methods. For instance, LPPC can be fabricated into epidermal electrodes and strain sensors by hand kneading, which are able to monitor ECG/EMG and movement signals of the human body, respectively. In addition, shaped through the customized molds, the flakes of LPPC exhibit effective EMI shielding performance after freeze-drying. Furthermore, the human-machine interaction based on TENGs is presented as a 3D printing demonstration of LPPC. This proposed viscoelastic conductive nanocomposite with tunable mechanical properties shows promising prospects for various applications in a range of fields.