Anisotropic hierarchical conductive network for stretch-insensitive tactile sensor with ultra-sensitivity and a broad detection range

Stretchable tactile sensors are promising for wearable electronics and soft robotics but often suffer from signal interference caused by tensile deformation. Here, we develop a stretch-insensitive piezoresistive tactile sensor featuring an anisotropic hierarchical conductive network that decouples pressure and strain signals. This structure combines magnetically aligned iron particles with a hierarchically organized liquid-metal network assembled through acoustic processing. The sensor maintains stable pressure output under tensile strains of up to 80% with a low tensile-to-compressive sensitivity ratio of 0.037%. It delivers ultra-high sensitivity, reaching 1,461 MPa −1 , across a broad pressure range from 400 Pa to over 1.6 MPa. The sensor enables accurate monitoring of dynamic mechanical inputs, demonstrated by Morse code recognition, high-impact pressure detection on joints, and discrimination of miniature Braille characters using a fabricated high-resolution array. These results highlight the sensor's potential for practical applications in electronic skin, human-machine interfaces, and advanced wearable systems.