A path toward transferable PEDOT: PSS-based capacitive sensors: electrical modeling and fabrication

Inácio, Pedro; Guerra, Rui; Stallinga, Peter

http://hdl.handle.net/10400.1/28463

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Autores

Inácio, Pedro

Guerra, Rui

Stallinga, Peter

Resumo(s)

This study presents the development and characterization of a novel transferable capacitive sensor based on poly (3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) as the primary electrode material. The electrodes were fabricated using an in-situ deposition technique that leverages the self-adhesive, flexible, and highly conductive properties of PEDOT:PSS to enable direct and stable contact with diverse surfaces for continuous, non-invasive hydration measurement. To evaluate their performance, PEDOT:PSS-based sensors were systematically compared with alternative electrode materials—including graphite, silver, gold, and indium tin oxide (ITO)—under controlled humidity conditions. A key innovation in this work is the integration of an ultra-lowcost impedance measurement system, enabling scalable and cost-effective capacitance-based hydration sensing. The study explores sensor fabrication, material characterization, and equivalent circuit modeling, quantifying the contributions of interfacial capacitance and dielectric properties. The results show that PEDOT: PSS electrodes exhibit enhanced hydration sensitivity at the electrode-dielectric interface, confirming that hydration-driven charge transport mechanisms dominate its capacitive response. This unique property allows PEDOT:PSS to detect subtle hydration fluctuations more effectively than conventional electrode materials, making it particularly well-suited for real-time monitoring in wearable electronics, biomedical diagnostics, and environmental sensing. Although physiological validation remains an essential next step, these findings establish a foundation for integrating PEDOT:PSS-based capacitive sensors into bioelectronics, flexible sensing platforms, and environmental monitoring technologies, facilitating the development of cost-effective, non-invasive hydration sensors across multiple fields.

Palavras-chave

Capacitive sensors Transferable PEDOT:PSS electrodes In-situ electrode fabrication Self-adhesive sensors Hydration-sensitive electronics Flexible electronics Impedance-based sensing