A conformable shape-stable self-healing polymer platform for continuous wireless arterial pulse monitoring.

Abstract

Self-healing polymers offer softness and conformability for skin-interfaced electronics. However, their flowable nature often causes gradual shape deformation, limiting their use in circuit-integrated devices. Here, we report a shape-stable self-healing polymer (SS-SHP) featuring a branched polymer network reinforced with reversible imine and hydrogen bonds. The SS-SHP maintained its original shape for 20 days with less than 5% reduction in storage modulus and exhibited a skin-like Young's modulus of 576 kPa, enabling conformal contact with microtextured skin. To achieve conductive circuits, incorporation of Ag flakes into the SS-SHP matrix yielded a self-healing conductor with stable surface resistance over time, avoiding the conductivity degradation typically observed in hydrogen-bonded SHPs. Using the SS-SHP as both substrate and electrode, we fabricated a wireless arterial pressure sensor with optical signal transmission that conforms to the wrist without external contact pressure and enables continuous pulse monitoring, including discrimination of non-pregnant and pregnant pulse waveforms.