Bio-templated Piezoresistive Yarn for High Sensitivity Movement Monitoring Textiles

Movement-sensing textiles are crucial for advancing wearable technology, providing solutions for real-time human motion monitoring. Textile-integrated piezoresistive sensors often struggle with balancing sensitivity and mechanical stability, alongside sustainability concerns regarding the use of traditional fossil-based materials like polyurethane and polydimethylsiloxane, commonly employed in sensor fabrication. Our study introduces bio-derived co-polyamide-starch (CoPA-SS) yarns as the substrate for piezoresistive sensors, leveraging the yarn's shape memory properties and reactive surface for further chemical modification essential for sensor development. Potato virus A (PV) particles serve as biological templates for creating a uniform silver nanoparticle (AgNP) coating, forming a piezoresistive network that enables long-range conductivity with minimal hysteresis. This network is covalently attached to the reactive surface of CoPA-SS yarns, enhancing sensor stability. These sensors exhibit linear stress-strain behavior across a 0-50% strain range, a gauge factor exceeding 400 at 10% strain, a fast response time of 150 ms, and stability over extensive cycling, including up to 7000 cycles at 50% strain. We also demonstrate sensor textile integration, allowing flexible and repeatable sensor placement without compromising textile integrity. Our pioneering approach of bio-templating AgNPs on PV particles positions this sensor among the highest-performing biobased sensors reported, paving the way for future high-performance wearable electronics.