Self‐Adhesive Conductive Elastomers for Gel‐Free Biopotential Recording

ABSTRACT The growth of wearable electrophysiology is accelerating demand for gel‐free biopotential electrodes that are skin‐conformal, comfortable for extended use, and stable under typical human motion. Here we report σPOMaC, a self‐adhesive, conductive, skin‐compatible elastomer based on poly(octamethylene maleate (anhydride) citrate) (POMaC), a citrate‐derived polyester with mechanical characteristics that are easily tunable via changes to monomer ratios and curing. Although POMaC is readily processed into soft structures, achieving robust electronic conductivity that survives curing, drying, and handling remains challenging, hindering its use in bioelectronic interfaces. To address this, we co‐formulate a soft conductor, poly(3,4‐ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS), with a surfactant, 4‐dodecylbenzenesulfonic acid (DBSA), into the POMaC prepolymer to generate conductive σPOMaC composites. Because these additives affect processing parameters and material properties, such as curing time and viscoelasticity, we optimized composition and processing to jointly achieve high conductivity (50 S/cm; ∼ 0.02 Ω·cm), skin‐appropriate adhesion (0.013 ± 0.004 N/mm on PDMS), and elastomeric compliance suitable for biopotential recording. Using optimized σPOMaC, we fabricated a custom chest patch featuring conformal ECG electrodes and demonstrated clear, high‐fidelity on‐body ECG waveforms comparable in morphology and timing to simultaneous recordings made using commercial Ag/AgCl electrodes. Together, these results position σPOMaC as a material platform for gel‐free, self‐adhesive, skin‐interfaced bioelectronic electrodes, enabling simplified application and improved interface with the end‐user and reducing disposable hydrogel waste in longitudinal monitoring.