Laponite Hydrogel-Templated Porous PDMS/Carbon-Filler Dielectric Layers for High-Performance Flexible Capacitive Pressure Sensors

Abstract Flexible capacitive pressure sensors are in urgent demand for applications such as wearable health monitoring and human–machine interfaces. Porous polydimethylsiloxane (PDMS) is widely used as a dielectric layer but suffers from poorly controlled pore structures and time-consuming fabrication, which limit sensor sensitivity and stability. Here, we propose a low-cost and highly efficient fabrication method using a Laponite inorganic hydrogel as an emulsion template to homogeneously disperse carbon nanotubes (CNTs) or graphite nanosheets (GNs) within a PDMS matrix, thus constructing a porous dielectric layer with a stable and uniform pore structure. We systematically investigate how filler morphology and structure, as well as loading, govern the pore architecture, mechanical behavior, and dielectric properties of the dielectric layer, and elucidate the intrinsic mechanism by which filler–pore coupling enhances sensor sensitivity. Experiments demonstrate that the PL/CNT-3 sensor (PL matrix filled with 3 wt % CNTs) achieves a maximum sensitivity of 2.58 kPa–1 and maintains a stable response over 10,000 loading and unloading cycles, enabling precise detection of both static and dynamic pressures as well as human joint motion signals. The fabricated sensor-array-integrated glove enables accurate recognition of diverse hand gestures. This work presents a straightforward and scalable approach for fabricating high-performance PDMS-based capacitive pressure sensors.