Polypyrrole linear actuation tuned by phosphotungstic acid

Abstract

Co-doping polypyrrole (PPy) with dodecylbenzenesulfonate and multicharged phosphotungstate anions (PT) from the phosphotungstic acid (PTA) led to free-standing PPy/DBS-PT films, which were studied for their linear actuation properties. FTIR and Raman spectra revealed that PT was successfully embedded in PPy/DBS during electropolymerisation. Isometric stress and isotonic strain measurements in aqueous electrolyte under various electrochemical experiments showed an increase in the obtainable strain and stress, which was attributed to the electrocatalytic role PTA plays during the electropolymerisation. This results in lower synthesis potential and the formation of more compact films in comparison to PPy/DBS films under equal conditions. With the improved structure as well as the higher-charged immobilized PT dopant, 17 times higher conductivities, 1.7 times higher redox charge, and 1.8 times higher specific capacitance were obtained (at equal frequency). Energy dispersive X-ray (EDX) spectra indicated that contrary to some other published works, the majority of PT stayed stably in the film during consecutive redox cycles.

Improving the Electrochemical Performance and Stability of Polypyrrole by Polymerizing Ionic Liquids

“…The results of the specific capacitance of the films showed that despite the different solvents, the values were close-in the range of 75 ± 2.4 F g −1 at 0.0025 Hz and, as expected, decreasing with increasing frequency [56]. Conducting polymers are defined as pseudo-capacitors due to their redox reactive nature [57], while strongly dependent on film thickness, specific capacity values of 100 F g −1 have been reached with PPy in LiTFSI-aq electrolyte under similar conditions [58]. As the PIL part of the material is not participating in the redox charging and with thicker films, the specific capacitance cannot reach as high, but on the other hand, the positively charged polycations inside the PPyPIL make the electrochemical behavior much more stable and also independent of the solvent.…”

Polypyrrole with Phosphor Tungsten Acid and Carbide-Derived Carbon: Change of Solvent in Electropolymerization and Linear Actuation

“…PPy doped with DBS − is one of the best studied types of conducting polymer materials, found in various formations in micro-fabrication [ 1 ] such as micro-robotic devices [ 2 , 3 ] biomedical applications [ 4 ], biochips to trigger cell growth over actuation [ 5 ] and, recently, smart textile fabrications [ 6 ]. Addition of charged molecules such as polyoxometalates (Keggin type [ 7 ], phosphotungstic acid (PTA, PW 12 O 40 3− )) forming PPyDBS-PT composites revealed strain in aqueous electrolyte in range of 5.2% [ 8 ]. Additional incorporation of meso-porous carbide-derived carbon (CDC) particles forming PPyDBS-PT-CDC (PPyCDC) linear films [ 9 ] had strain in the range of 12% while PPyDBS linear actuators strain values varied at 4–6% strain depending on the choice of electrolyte applied [ 10 ].…”

Review of Soft Linear Actuator and the Design of a Dielectric Elastomer Linear Actuator

“…As for polypyrrole, Hara et al [68] reached the stress of 20.4 MPa with TBACF 3 SO 3 and the strain of 26% with bis(trifluoromethanesulfonyl)imide (TFSI) anion. New conducting polymers have been recently fabricated with different dopants, such as PPy doped with dodecylbenzenesulphonate (DBS) (PPy/DBS) [69], and further with phosphotungstate anions (PT) to give PPy/DBS-PT [70] and with carbide-derived carbon (CDC) to give PPy/DBS-CDC-PT [71] linear actuators. These conducting polymers have been applied in wearable devices [72] and even in tissue engineering [73], which are shown in Fig.…”