Simple route to performance modulation of resistive strain sensor based on strain-engineered stretchable substrate with customized hard template

Abstract

Despite recent remarkable advances in wearable strain sensors, it remains challenging to achieve a high sensitivity and high stretchability simultaneously within a single device. Herein, we present a simple yet universal route to geometric modulation of elastomeric substrates based on customized hard templates for systematically optimizing the sensing performance of stretchable strain sensors. The hard template is simply prepared by patterning a thin plastic sheet using a facile cut-patterning process and entirely embedded into elastomeric substrates to redistribute the surface strain upon stretching in a programmable manner. The proposed strain-engineered stretchable (SES) substrates with various designs of the hard templates are easily integrated with silver nanowire (AgNW)/elastomer composite sensory films and play a crucial role in achieving balanced sensing performance of the strain sensors. The AgNW/SES (AS) strain sensor exhibits a high stretchability (68%) and high mechanosensitivity (gauge factor of ∼4.5 at 0–25% and ∼33 at 25–68%) while exhibiting long-term performance stability (1000 stretching cycles at 30% strain). Owing to their excellent sensing performance and mechanical flexibility, the AS strain sensors are successfully used to monitor a wide range of strains caused by human activities during exercise, indicating the potential as practical wearable devices for real-time motion detection.