Enhancing flexoelectricity in PEDOT:PSS polymer films with soft treatments

• Published in: Journal of applied physics Vol. 130; no. 1
• Main Authors: Saadeh, M., Aceta, Y., Frère, P., Guiffard, B.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 07.07.2021
• Subjects: Addition polymerization; Aluminum; Applied physics; Electrodes; Engineering Sciences; Ethanol; Gold; Inorganic materials; Methanol; Other; Polymer blends; Polymer films; Polymers; Polystyrene resins; Stainless steels; Xylitol
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/5.0052302

We report the use of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) as a transducing material in the fabrication of mechanical-to-electrical conversion devices based on the flexoelectric-like response of this polymer. Devices are made in a cantilever-based three-layer stainless-steel/PEDOT:PSS/top metal electrode configuration to assess the effective transverse flexoelectric coefficient μ 12 ′. We investigated the influence of the nature of the top electrode in the flexoelectric response comparing samples with gold and aluminum top electrodes and demonstrated the huge impact of adding a small fraction of a second dopant such as xylitol to the PEDOT:PSS polymer blend and the benefits of a post-treatment of the polymer film with ethanol and methanol on the flexoelectric coefficient. The combination of xylitol addition and the rinsing of the polymer films with ethanol and methanol, along with the use of gold as a top electrode, led to a significant improvement of μ 12 ′ to ca. 24 μC m−1, which is in the range of those reported for high permittivity oxide materials. These findings support the use of conjugated polymers as an alternative to inorganic materials in flexoelectric-based applications, where large flexibility is required.