Actuation electrolyte, effect

The conductance of electrolytes is caused by ions which are brought into motion by the effect of the electrical field. The velocity of the ions increases from the first moment the current is led into the solution but it attains a constant value as soon as the actuating force equals the resistance encountered by the ions on their respective path (viscosity of the medium and electrostatic... 

K. Onishi, S. Sewa, K. Asaka, N. Fujiwara and K. Oguro, The effects of counter-ions on characterization and performance of a solid polymer electrolyte actuator, Electrochim. Acta, 2001, 46, 1233-1241. 

Rbder-Roith, U., Rettig, R., Roder, T, Janek, X, Moos, R. and Sahner, K. (2009), Thick-flhn solid electrolyte oxygen sensors using the direct ionic thermoelectric effect. Sensors and Actuators B Chemical, 136(2), 530-5. 

Fig. 1.2 Schematic representation of the actuation mechanism for a CNT actuator. When a bias is applied to CNTs that are submerged in an electrolyte, ions will migrate to the surface of the CNTs, which is offset by the rearrangement in their electronic structure. This phenomenon, coupled with Coulombic effects, results in actuation [7]. Materials Today 2007, reprinted with permission...

Sensors Actuator Electrode for Secondary Battery, Solid Electrolytic Capacitor or Supercapacitor Field Effect Transistor Electromagnetic Interference Absorbing Material... 

Experiments were conducted on trilayer PPy actuators to validate the effectiveness of the redox level-dependent admittance model. The electrolyte used was tetrabutylammonium hexafluorophosphate (TBA+PFg) in the solvent propylene carbonate (PC). The samples were predoped with PFg during fabrication, and the nominal concentration Co in the absence of DC bias was estimated to be fOOO mol/m based on the deposition conditions. In experiments different values of Cq were achieved by applying appropriate DC biases. Sinusoidal voltages of amplitude 0.05 V and frequency 0.08 — 200 Hz were superimposed on the DC voltage, as perturbations, for the measurement of admittance (or equivalently, impedance) spectra. 

Yoon J, Hunter G, Akbar SA, Dutta PK (2013) Interface reaction and its effect on performance of a C02 sensor based on Lio.35Lao.55Ti03 electrolyte and Li2C03 sensing electrode. Sensors and Actuators B... 

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These two effects were clearly seen in a study undertaken by Kara et al. [36]. In their work, PPy doped with bis(trifluoromethanesulfonyl)imide (TFSI) was actuated in various water/propylene carbonate (PC) solutions containing LiTFSI. The optimum performance of 23.6 % maximum strain at a strain rate of 10.8 % s was achieved within an actuation solution that consisted of 60 % water and 40 % PC. Improvements in both the strain rate and the maximum strain were seen with actuation in LiTFSI electrolytes of water/PC blended solvents over actuation in electrolytes of either water or PC alone. The improved actuation was attributed to the fact that a greater swelling occurred from the PC solvent (enabling a faster and easier ion transfer) and an improvement in the ionic conductivity from the water solvent (enabling a better charge transfer). As such, the optimised performance for this system was realised at 40 % PC. 

A major advantage obtained from ionic liquid electrolytes, however, is a dramatically increased actuation stability on extended cycling. This effect was clearly illustrated in a... 

The stability of actuators is also influenced by the mechanical load applied and a further benefit of EL electrolytes is highlighted by sueh studies [38]. As shown in Figure 10.8 the actuation strain decreases rapidly in a PC electrolyte (TBA.PFg) when actuation strain was measured at higher isotonic stresses. The strain remains approximately the same, however, as the stress increased and an IL electrolyte was used. The effect of applied stress on the actuation strain observed is related to the Young s modulus of the polymer, as explained below. 

An ionometric system for the analysis of electrolyte solutions has been developed Planar chip structures of ion sensitive field effect tansistors (ISFET s) and ion selective electrodes (ISE s) are used as sensors Their layout allows an easy preparation of the ion sensitive membrane and also a very simple electrical contacting The sensor chips can be clipped to small volume flow-through cells for dynamic measurements An advanced electronic device was developed for measuring both, the ISFET and the ISE signals This system is usefial for basic investigations of ion sensitive materials and can be integrated comfortably into electroanalytical sensor/actuator microsystems... 

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