Multifunctional Flexible Fibrous Ionogel with Superior Breathability, Stretchability, Antimicrobial and Self-Adhesive Properties for Wearable Electronics

Ionogels have attracted considerable attention in wearable strain sensors owing to their inherent flexibility, skin-like conformability, and capability for detecting biomechanical signals. However, most existing ionogel-based flexible strain sensors still suffer from limited stretchability, low mechanical strength, inadequate self-adhesion, and poor breathability, which constrain their practical applications. In this work, a strategy for constructing fiber-structured ionogels was presented, integrating excellent mechanical robustness, enhanced breathability, reliable self-adhesion, and multistimuli sensing capabilities. An ultrathin ionogel (0.1 mm thick) was fabricated via an entangled network formed through physical interactions such as hydrogen bonding and electrostatic forces between thermoplastic polyurethane (TPU) and ionic liquid (IL) fibers, and reinforced with few-layer black phosphorus (BP), without the use of cross-linking agents or chemical initiators. The resulting ionogel (BP@TPU ionogel) exhibits a high tensile strength of 17.18 ± 1.35 MPa, toughness of 13.14 ± 1.38 MJ m–3, modulus of 8.99 ± 1.65 MPa, and a notable elongation of 230.33 ± 2.57%, along with exceptional breathability (190.94 g m–2,24 h). Moreover, the incorporation of a waterborne polyurethane (WPU) adhesive layer confers strong adhesion, ensuring durable and repeatable self-adhesive performance even under humid conditions or prolonged use. The BP@TPU ionogel-based strain sensor leverages a synergistic dual conductive framework─comprising both electronic BP and IL pathways─to deliver high sensitivity (gauge factor, GFmax = 2.05) and a wide sensing range (0–110%). The device reliably captures a broad spectrum of human physiological signals, including various joint movements, real-time temperature fluctuations, and subtle motions such as swallowing and respiration. Even after 1000 mechanical cycles, the sensor maintains stable signal output, underscoring its great promise for applications in next-generation smart wearables, electronic skin, and human–machine interfaces.