Breathable Ultrathin Film Sensors Based on Nanomesh Reinforced Anti‐Dehydrating Organohydrogels for Motion Monitoring

Abstract

Flexible hydrogel film sensors have great advantages as human–machine interfaces for conformal contact with bio‐tissues, but suffer from weakness and dehydration, compromising flexibility and performance. Here, a breathable, highly stretchable, and anti‐dehydrating ultrathin organohydrogel film as a skin‐attachable strain sensor for long‐term motion monitoring is developed. An electrospun TPU (eTPU) nanomesh with hidden strength is used as skeleton to host in situ free radical polymerization of 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS) and acrylamide (AAm) to form an interpenetrating double network organohydrogel with glycerol and water as solvent. Extensive hydrogen bonding between eTPU nanomesh and P(AMPS‐co‐AAm) network yields ultrathin organohydrogel film (≈200 µm) with synergetic deformation and energy dissipation upon stretching, leading to record‐high stretchability up to 920%, fracture toughness of 20.14 MJ m−3, fracture energy of 10 000 J m−2, and robustness over 4000 notched stretching cylcles to 50% strain. The binary glycerol/water solvent imparts excellent anti‐dehydration at room temperature for 10 d, and stable sensory performance from −20 to 60 °C. With a high water vapor transmission rate of 1.3 kg m−2 d−1, the film sensor ensures comfortable skin contact for continuous knee flexion monitoring throughout the day with stable signals. These organohydrogel film strain sensors are promising for wearable and long‐term motion monitoring applications.