Multilevel Asymmetric Monolithic Stretchable Device for Omnidirectional Strain Sensing

Abstract Omnidirectional strain sensors have attracted considerable attention due to their potential in flexible electronics applications. However, most existing designs based on multi‐unit integrated arrays require multiple electrodes and complex signal acquisition systems, which significantly limit their practicality in portable applications. Herein, a monolithic strain sensor with a multilevel asymmetric architecture is proposed for high‐precision direction recognition. The sensor features a capacitor structure composed of a heterogeneous dielectric substrate and two asymmetric capacitor electrodes, enabling simultaneous acquisition of independent resistive and capacitive signals using only three electrodes. By incorporating Ecoflex and Ecoflex‐polydimethylsiloxane with a modulus difference exceeding an order of magnitude to construct dielectric substrate featuring heterogeneous sector‐shaped structure, significant asymmetric stress distribution is achieved to enhance directional discrimination. Furthermore, a mathematical model is developed to quantify the signal discreteness across various stretching directions, and a data‐driven inverse design strategy is employed to efficiently screen 2073600 structures, identifying asymmetric sensing layer configurations with superior direction recognition performance. Assisted by machine learning, the sensor achieves a direction recognition (15° resolution) accuracy of 98.6% and precise strain magnitude (50% range) prediction. Benefiting from its excellent omnidirectional sensing capability, the sensor realizes accurate localization of 12 directional touch points, demonstrating great potential for flexible electronics.