A hierarchically structured fibrous sensor with temperature-responsive adhesion for wearable applications

Abstract

Flexible self-adhesive wearable strain sensors have attracted significant attention for their ability to conform closely to human skin and accurately capture physiological signals. However, many existing designs struggle to balance sensing performance with essential comfort-related features such as breathability, waterproofness, and on-demand removability. This paper reports a hierarchically structured nanofiber-network strain sensor fabricated via electrospinning, integrating three layers: a sensing layer, a spacer layer, and an adhesive layer. The all-fiber architecture provides excellent flexibility, stretchability, and environmental adaptability, which can closely mimick the mechanical properties of human skin. The sensing layer is composed of multi-walled carbon nanotubes/carbon black/thermoplastic polyurethane (MWCNT/CB/TPU), which can exhibit high sensitivity, linearity, rapid response time (130 ms), and excellent cycling stability (2,000 cycles). The adhesive layer, made of electrospun poly(N,N-dimethylacrylamide, PDMA) nanofibers, forms a strong interface with the skin through hydrogen bonding and van der Waals interactions, maintaining adhesion even in humid conditions. Incorporating phase-change monomers such as octadecyl acrylate and lauryl acrylate yields a melting point of ∼38.1 °C, enabling reversible, temperature-triggered detachment. This work addresses the challenge of combining high performance with comfort, representing a paradigm shift in wearable sensing by enabling imperceptible monitoring and broadening applications in personal healthcare and interactive electronics. Graphical abstract: [Figure not available: see fulltext.]