Device electrochemical actuators

In recent several years, super-capacitors are attracting more and more attention because of their high capacitance and potential applications in electronic devices. The performance of super-capacitors with MWCNTs deposited with conducting polymers as active materials is greatly enhanced compared to electric double-layer super-capacitors with CNTs due to the Faraday effect of the conducting polymer as shown in Fig. 9.18 (Valter et al., 2002). Besides those mentioned above, polymer/ CNT nanocomposites own many potential applications (Breuer and Sundararaj, 2004) in electrochemical actuation, wave absorption, electronic packaging, selfregulating heater, and PTC resistors, etc. The conductivity results for polymer/CNT composites are summarized in Table 9.1 (Biercuk et al., 2002). 

Lu, W., I.D. Norris, and B.R. Mattes. 2005. Electrochemical actuator devices based on polyaniline yarns and ionic liquid electrolytes. Aust J Chem 58 263. 

Li PY, Shih J, Lo R, Saati S, Agrawal R, Hiunayun MS, Tai YC, Meng E (2008) An electrochemical intraocular drug delivery device. Sens Actuators A-Phys 143 41-48... 

Electroactive network membranes as artificial muscles, direct methanol fuel cells Electrochemical actuators, micromechanical systems, on-demand devices, chemical sensors, antibacterial nanocomposite materials, dye sensitized solar cells, microwave absorbing materials... 

Figure 10.4 Complete polyaniline actuator assembly consisting of eight PANi twisted fibre yarns inserted in a hollow PANi fibre (counter electrode) containing liquid electrolyte. A porous separator prevents short circuiting (Reproduced from Australian Journal of Chemistry, Electrochemical actuator devices based on polyaniline yarns and ionic liquid electrolytes by Lu, W., Norris, I.D. and Mattes, B.R., 58, 263-9. Copyright (2005) CSIRO Publishing).

Active catheterization will pave the way for minimally invasive medical diagnosis and treatments that involve less risk and pain for patients and less complication for doctors. Electroactive polymer (EAP) actuators are good candidates for use in active catheters due to their biocompatibility, low cost, large strain, low actuation voltage and ease of fabrication. However, electrochemical actuation of these devices involves using ionic electrolytes which require either encapsulation or perhaps direct use of internal fluids. 

The most commonly employed type of actuator on the microscale is the bilayer, typically attached to a single rigid plate. The bilayer comprises the polymer and a metal film. Since the device is actuated electrochemically, a nonreactive noble metal is usually used, typically gold or platinum. The electrode serves both mechanical and electrical functions. It is the non-volume-changing layer that converts inplane strain in the conjugated polymer... 

For electrochemical actuators driven by flow of a constant current (/), any change of the working energetic (U) conditions (mechanical, thermal, chemical, electrical) will be sensed by the instantaneous adaptation of the device potential (E) evolution, during acmation, to the new working energetic conditions potentio-metric sensors. 

Figure 5.5.11 / schematic drawing of an in situ EDX analysis system for the electrochemical actuator device... 

Figure 5.5.14a indicates that the bending behavior of a l-ethyl-3-methylimidazoliumbis(trifluoromethane-sulfonyl)amide ([EtMeIm][Tf2N])-based electrochemical actuator prepared in this investigation at different cycles. The displacement clearly increases with increasing cycle number. We analyzed the device by the in situ... 

Conducting polymers have found applications in a wide variety of areas,44 45 and many more have been proposed. From an electrochemical perspective, the most important applications46 appear to be in batteries and supercapacitors 47,48 electroanalysis and sensors49-51 electrocatalysis,12,1, 52 display and electrochromic devices,46 and electromechanical actuators.53... 

Apart from the promising electrochemical properties that will be exhaustively discussed through this chapter, carbon nanotubes have become a hot research topic due to their outstanding electronic, mechanical, thermal, optical and chemical properties and their biocompatibility. Near- and long-term innovative applications can be foreseen including nanoelectronic and nanoelectromechanical devices, held emitters, probes, sensors and actuators as well as novel materials for mechanical reinforcement, fuel cells, batteries, energy storage, (bio)chemical separation, purification and catalysis [20]. 

Since the appearance of the redox [ii, iii] and conducting [iv] polymer-modified electrodes much effort has been made concerning the development and characterization of electrodes modified with electroactive polymeric materials, as well as their application in various fields such as -> sensors, actuators, ion exchangers, -> batteries, -> supercapacitors, -> photovoltaic devices, -> corrosion protection, -> electrocatalysis, -> elec-trochromic devices, electroluminescent devices (- electroluminescence) [i, v-viii]. See also -> electrochemically stimulated conformational relaxation (ESCR) model, and -> surface-modified electrodes. 

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