journal article·2025-07-15Open access

Highly conductive polymer with vertical phase separation for enhanced bioelectronic interfaces

Jiahuan Qiu, Yuyao Lu, Xinyuan Qian, Junxian Yao, Chengcan Han, Ziliang Wu, Hui Ye, Guorong Shan, Qiang Zheng, Kaichen Xu, Miao Du

npj Flexible Electronics· Volume 9· Issue 1

Abstract

Conductive polymers like poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT: PSS) are key materials in bioelectronics, but balancing ultrahigh conductivity with long-term tissue contact stability remains a challenge. Here, we present a solvent-mediated solid-liquid interface doping strategy to engineer vertically phase-separated (VPS) PEDOT: PSS films. By adjusting thickness and doping solvents, a thicker PEDOT: PSS film with a strong VPS structure was achieved, featuring a higher PSS/PEDOT ratio on the surface and a lower ratio at the bottom. Doping the pristine film with a metastable liquid-liquid contact solution enables gradual PSS migration and a significant component gradient, yielding films with a hydrophilic surface and one of the highest reported conductivities ( ~ 8800 S cm −1 ) for bioelectronic devices. The films patterned by laser processing present high-fidelity signal acquisition, and excellent electrochemical stability. With low impedance and long-term biocompatibility, they are employed for real-time wearable and implantable sensors for electrophysiological monitoring, showcasing broad potentials in bioelectronics and human–machine interactions.
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Research context

OpenAlex topics: Advanced Sensor and Energy Harvesting Materials · Conducting polymers and applications · Advanced Materials and Mechanics

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