Matrix Swelling-Induced Precracking in Graphene Woven Fabric for Ultrasensitive Strain Sensors

The growing demand for highly sensitive flexible strain sensors in applications such as wearable electronics, healthcare monitoring, and environmental sensing has driven the development of materials capable of detecting subtle deformations with high precision. Herein, we introduce a precracked strain sensor based on solvent-swollen graphene woven fabric/polydimethylsiloxane (sGWF/PDMS) composites, designed to achieve ultrahigh gauge factors (GFs) and enhanced responsiveness to minor deformations. By utilizing PDMS swelling to induce network microcracks within the graphene structure, the sGWF/PDMS composites exhibit substantially improved sensitivity compared to traditional graphene-based strain sensors. Systematic in situ SEM analyses reveal that these preexisting microcracks expand readily under minor strain, resulting in rapid resistance changes that underpin the high sensitivity achieved. With GFs reaching up to 82,378 at only 2.8% stretching strain, the sGWF/PDMS composites demonstrate excellent performance across various applications, including human motion detection such as monitoring pulses, eye blinks, and speech-related movements, as well as detecting environmental disturbances such as water surface ripples. These findings highlight matrix-swollen composites as a promising platform for high-sensitivity, low-strain detection, offering great potential for advancements in wearable electronics, environmental monitoring, and other precision sensing applications.