Carbon Nanotube-Enhanced Liquid Metal Composite Ink for Strain Sensing and Digital Recognition

With the rapid development of wearable electronic devices, there is an increasing demand for high-performance flexible strain sensors. In this study, LM/CNT composite ink was prepared by the ultrasonic dispersion method, and the electron transfer between carbon nanotube (CNT) and liquid metal (LM) was utilized to construct a three-dimensional conductive network, which effectively enhanced the wettability and conductivity of the ink and the tensile performance of the sensor. Flexible strain sensors were prepared based on LM/CNT conductive ink, and the effects of different electrode patterns on sensor performance were explored. The stress distribution of linear (P I), folded (P II), and serpentine (P III) electrode patterns under tensile conditions was systematically investigated by theoretical analysis of material mechanics and finite element simulation. The experimental results show that the P III type has the smallest stress concentration and the highest sensitivity under various strains. In addition, the P I type sensors have the function of direction recognition due to their different responses to anisotropic deformations. Based on the P I type sensor, we successfully prepared a triboelectric nanogenerator (TENG) and demonstrated its potential application in the field of digital recognition by utilizing its friction power generation and orientation recognition properties.