Tunable flexible capacitive sensor for dynamic pressure monitoring.

Abstract

Flexible capacitive pressure sensors have gained widespread application in health monitoring, robotics, and structural diagnostics. However, conventional designs that rely on flat or micropatterned dielectric layers typically offer high sensitivity only at low pressures and possess limited tunability, which makes them unsuitable for dynamic or harsh environments. In this study, we present a tunable capacitive pressure sensor fabricated via buckling-guided assembly and laser cutting, which transforms 2D precursors into 3D cage-like architectures. The sensor exhibits pressure-dependent sensitivity, characterized by low sensitivity under small loads and significantly enhanced sensitivity at higher loads due to nonlinear variations in electrode spacing. It achieves outstanding performance, including high durability over 6000 cycles, a low detection limit (~2 Pa), minimal hysteresis (~4%), and rapid response and recovery times (131/140 ms). Finite element analysis and experimental validation confirm the tunable mechanical response and accurate electromechanical behavior enabled by geometric design. The sensor also allows reversible tuning through lateral strain and liquid encapsulation, enhancing environmental robustness. Moreover, a compression-induced rotation mechanism further improves sensitivity by increasing electrode overlap during loading. Wind tunnel experiments validate the sensor's performance under extreme conditions, demonstrating strong potential for practical applications.