Highly piezoresistive compliant nanofibrous sensors for tactile and epidermal electronic applications

Soft, sensitive, and conformable strain sensors can provide tactile sensation to prosthetic limbs and can be used for epidermal and wearable health monitoring. High strain sensitivity is often achieved by using piezoelectric ceramics, such as lead zirconate titanate (PZT), with known issues for large-area scalability, rigidity, and biocompatibility. Here, we report a nature-inspired, piezoresistive, soft, and benign core–shell nanofibrous sensor that exhibits an unprecedented gauge factor in excess of 60, arising from a reversible disjointing/jointing of a large number of interfiber junctions, consequently changing the current path and resistance in response to both tensile and compressive strains. Nanofiber textile sensor arrays are demonstrated with fast, low-voltage, accurate, and repeatable sensing over 1000 cycles for epidermal monitoring of limb and musculoskeletal movements and radial pulse waveform, for real-time monitoring of simulated intermittent Parkinson’s tremors, and for biaxial tactile sensing and localization of point of touch.