Ultrasoft, Stretchable, and Adhesive Conducting Polymer Ionogels for Reliable Wearable Sensors

Wearable sensors require conductive soft materials that combine high stretchability, conformal adhesion, and long-term stability for reliable operation in complex environments. However, conventional conducting polymer gels fabricated in aqueous media struggle to simultaneously integrate these properties due to difficulties in forming stable conductive networks and poor environmental tolerance. Here, an ultrasoft, highly stretchable, and adhesive conducting polymer ionogel is developed via an ionic liquid-mediated in situ polymerization. The ionic liquid provides a favorable medium for the in situ polymerization of pyrrole (Py), producing a well-connected polypyrrole (PPy) conductive network interpenetrated within a poly(acrylic acid-co-N-2-hydroxyethyl acrylamide) (P(AA-co-HEAA)) ionogel, which is tightly integrated with the polymer matrix through abundant noncovalent interactions. The resulting conducting polymer ionogel exhibits an ultralow modulus (4.6 kPa), high stretchability (435%), and high conductivity (0.60 S m^-1), along with good adhesion and extreme environmental stability. This ionogel demonstrates high strain sensitivity across 0.1%-400% with excellent reliability under harsh conditions, enabling precise monitoring of diverse human motions. Furthermore, it can also serve as a conformal bioelectrode with low interfacial impedance for high-fidelity electrophysiological signal acquisition. This work establishes a generalizable strategy for developing high-performance conducting polymer gels for next-generation wearable bioelectronics.