Band-aid based piezoresistive sensor with hierarchical multiscale architectures for high-sensitivity and wide-range pressure monitoring

Flexible piezoresistive sensors are crucial for wearable electronics. Conventional approaches predominantly enhance sensitivity and detection range through innovations in conductive materials, sensor substrates, or sophisticated microstructure engineering. This study presents a novel approach using commercial band-aid as multifunctional piezoresistive sensor substrates, utilizing their inherent structural properties. This substrate is functionalized through immersion into a multi-walled carbon nanotubes (MWCNT) and cellulose nanofibers (CNFs) composite dispersion, forming a nanoscale conductive film while preserves the native microscale patterns. These patterns amplify localized pressure responses, thereby enhancing sensitivity. Simultaneously, the conductive band-aid is assembled into a millimeter-scale arched architecture that optimizes the sensitivity-range trade off: under low stress, the minimal initial contact area optimizes sensitivity, while the arch design stabilizes large deformations, extending the measurable pressure range. This cross-scale integration synergizes stress redistribution and dynamic conductive pathway adjustments, enhancing contact area homogeneity under pressure. The resultant sensor demonstrates exceptional performance including high sensitivity (66.8 kPa −1 ), broad detection range (0–219.2 kPa), rapid response/recovery times (1 ms/4 ms), exceptional durability (10,000 cycles), and ultra-low detection limit (7 Pa). Moreover, the methodology addresses scalability and cost barriers by utilizing mass-produced, biocompatible band-aids as off-the-shelf substrates, bypassing complex and costly nanofabrication processes. By harmonizing material accessibility, structural ingenuity, and multi-functional sensing performance, this approach not only resolves enduring trade-offs between sensitivity, range, and durability in wearable sensor design but also establishes a scalable platform for next-generation epidermal electronics.