Isotropic and Strain-Insensitive Cellulosic Triboelectric Materials Enabled by the Hofmeister Effect.

Abstract

Achieving high-fidelity tactile sensing under dynamic deformation is a key bottleneck for the practical application of flexible electronics. However, conventional sensing materials face mechanical mismatch with biological tissues and signal distortion caused by stretching. In this work, we used the Hofmeister effect to remodel the hydrogen-bond network and developed an isotropic, strain-insensitive triboelectric material (ISTN). Hydrogen-bond-network remodeling is achieved via the Hofmeister effect, which regulates anion-water-polymer interactions to induce polymer chain aggregation and crystallization. The surface micropyramid array gives ISTN efficient load transfer and dispersion, allowing the sensor to maintain stable electrical output under biaxial stretching. In addition, ISTN achieves a wide range of tunable mechanical properties, addressing the issue of interfacial mechanical mismatch. The ISTN pressure sensor, combined with machine learning, enables efficient joint motion recognition. This work holds great potential for applications in human-machine interaction and healthcare.