Carbon nanotube-based nanocomposite electrodes using a water-soluble PEDOT derivative for high-performance actuators

Poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) is available commercially as an aqueous dispersion of colloidal particles; however, PEDOT:PSS has several technical limitations, such as insolubility in water and organic solvents , that affect the fabrication and performance of products. This study synthesized a water-soluble PEDOT derivative that incorporated a sulfonic acid group (S-PEDOT). Subsequently, highly conductive super-growth single-walled carbon nanotubes (SG-SWCNTs), S-PEDOT, and two different ionic liquids (ILs) were used to fabricate nanocomposite electrodes and actuators that exhibited both electrochemical double-layer and faradaic capacitance. A comparison between the electromechanical and chemical properties of the S-PEDOT- and PEDOT:PSS-based electrodes revealed that they had similar volume and surface resistivities. The specific capacitances of the SG-SWCNT/poly[4-{(2,3-dihydrothieno[3,4- b ][1,4]dioxin-2-yl)methoxy}butane-1-sulfonic acid] (S(1,4)-PEDOT)/IL composite electrodes surpassed those of their poly[4-{(2,3-dihydrothieno[3,4- b ][1,4]dioxin-2-yl)methoxy}butane-2-sulfonic acid] (S(2,4)-PEDOT)- and PEDOT:PSS-based counterparts. The S-PEDOT-based composite electrode actuators, particularly those with the IL EMI[BF 4 ], demonstrated higher maximum strains than the PEDOT:PSS-based composite electrode actuators. The frequency-dependent strain was accurately predicted using a kinetic model grounded in double-layer charging, which indicated that the composite actuator exhibited both electrochemical double-layer and faradaic capacitance. Compared to the PEDOT:PSS-based electrodes, the S-PEDOT-based electrodes achieved a higher specific capacitance (particularly in the case of S(1,4)-PEDOT), higher maximum strain, and comparable conductivity, highlighting their potential for biomedical and electronic applications. • Water-soluble S-PEDOT is used to fabricate nanocomposite electrodes and actuators. • S-PEDOT-based electrodes perform better than PEDOT:PSS-based electrodes. • S-PEDOT-based actuators show electrochemical double-layer and faradaic capacitance. • S-PEDOT offers good conductivity, specific capacitance, and maximum strain. • Electrodes are robust, pliable, and combine benefits of PEDOT derivatives/IL/SWCNTs.