A Noninterfering Dual-Module E-Skin for Direction Strain and Pressure Sensing

Biomimetic electronic skins (e-skins) possessing strain-pressure sensing characteristics are widely applied in wearables for comprehensive mechanical stimuli sensing. However, dual-module e-skins with strain-pressure sensing performance show an innate defect that the strain causes interference with the accuracy of pressure sensing. Herein, a noninterfering dual-module e-skin (NIDM-skin) has been developed to achieve decoupled strain-pressure sensing via interlocked alteration of PDMS with different elastic moduli. In this research, a carbon nanotube-oriented thermoplastic polyurethane nanofiber membrane (CNT-OTPU) serves as a conductive network to realize direction strain sensing (gauge factor of 638 under 275% strain) and is encapsulated by low-modulus polydimethylsiloxane (LPDMS). High-modulus polydimethylsiloxane (HPDMS) is employed as a triboelectric material for pressure sensing, which is strain insensitive (under 200% strain) due to modulus mismatch. With the stable pressure sensing ability on the deformable surface, magnitude, and direction recognition capacity of strain, NIDM-skin displays great potential in soft robotics and medical rehabilitation for accurate identification.