Revealing the flexoelectric‐like response of poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) thin films

Abstract

In the last decade, the polymeric poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) semiconductor has been widely studied for their electrical and electrochemical properties and used in various applications such as flexible and transparent electrodes, optoelectronics and thermoelectric devices. Here, we report the intrinsic electromechanical coupling in trilayered stainless steel/PEDOT:PSS/Aluminum composites. The PEDOT:PSS thin film integrated in the multi‐layer serves as the transduction material itself and yields a remarkable flexoelectric‐like response when the cantilever shaped‐ device assembly is subjected to beam bending. Two orders of magnitude larger flexoelectric coefficients (up to μ′12 = 6 μC/m) were obtained for semiconducting PEDOT:PSS thin films, in comparison with those measured for insulating polymers. Besides, it is observed that flexoelectric effect may be enhanced when the conductivity of the trilayer device increases to a certain extent, especially after a simple dilution treatment that induces partial removal of excess hydrophilic PSS. These first results may open a new avenue for simply preparing flexible and highly sensitive curvature sensors with single electroactive semiconducting polymer layer between metal electrodes.

Large Curvature Sensors Based on Flexoelectric Effect in PEDOT:PSS Polymer Films

“…In previous work, 31 it was experimentally observed that PEDOT:PSS films deposited onto stainless steel substrate, with conductivity greater than 10 −2 S/m do not exhibit a flexoelectric-like effect. The same behavior is observed with the Relative permittivity, dielectric loss factor, and dynamic conductivity measurements for PEDOT:PSS solutions (1:6 ratio) on different substrates were also performed (see the section entitled "Dielectric Characterization of PEDOT:PSS on Different Substrates" in the Supporting Information).…”

“…In previous work, it was experimentally observed that PEDOT:PSS films deposited onto stainless steel substrate, with conductivity greater than 10 –2 S/m do not exhibit a flexoelectric-like effect. The same behavior is observed with the freestanding PEDOT:PSS (1:2.5) films in this study, which tends to show that PEDOT:PSS (1:2.5) is not suitable for flexoelectricity.…”

“…Recent work on the flexoelectric response of the archetypal conducting (3,4-ethylenedioxythiophene)-poly­(styrenesulfonate) PEDOT:PSS polymeric blend has been conducted by Saadeh et al, where the polymer film has been deposited on a stainless steel substrate. They obtained a large flexoelectric coefficient of ∼3.4 μC/m, which was attributed to the overall high polarizability of PEDOT:PSS induced by the electrical double layer formed between the positively charged oligomer of PEDOT + and negatively charged chains of PSS – .…”

Biomechanical behaviour of PEDOT:PSS-based hydrogels as an electrode for stent integrated enzyme biofuel cells

“…Conductive polymers contain conjugated structures in backbone, which provide electrical conductivity due to the π bonds overlapping and creating of large chain segments where π-electrons are delocalized. Popular conjugated polymers, such as polyaniline, polypyrrole and polythiophene are extensively used in various applications since they show satisfying processability and high electrical conductivity [15,16,17]. Among others, polythiophene derivative, poly(3,4-ethylenedioxythiophene) (PEDOT), in a complex with poly(styrenesulfonate) (PSS) exhibits many valuable properties, in particular, water solubility, electrochemical and thermal stability, and relatively large conductivityup to 900 S cm À1 [18].…”