Bilayer actuators

The substitution of the two-sided tape with a film of an ionic conductor gives (Fig. 24) a triple-layered muscle working in air.114 The tape now acts as a solid electrolyte. Nevertheless, the system only works if the relative humidity in air surpasses 60%. Under these conditions, movements and rates similar to those shown by a triple layer working in aqueous solution were obtained. This device was developed in cooperation with Dr. M. A. De Paoli from the Campinnas University (Campinnas, Brazil). At the moment several groups are developing actuators, muscles, and electrochemomechanical devices based on bilayer or multilayer structures.115-125... 

F. Mizutani, Y. Hirata, S. Yabuki and S. Iijima, Flow injection analysis of acetic acid in food samples by using trienzyme/poly(dimethylsiloxane)-bilayer membrane-based electrode as the detector, Sens. Actuators B Chem., 91(1-3) (2003) 195-198. 

Thin elastomeric coatings or coverings, which also serve as a moisture barrier, act as skin, preventing evaporation and leakage of the electrolyte solution(s). This allows these actuators to be fiiUy operational anywhere. Using a bilayer coating can provide for a compact actuator, where the innermost layer (the layer closer to the EAP) is a conductive layer and serves as the external electrode (Fig. 4.27). 

Figure 9.19 Simultaneous 2/imx 2 pm image of film topography (left) and surface potential (right) of a seven-bilayer, 30 nm MFeCIs, Ppy/SPS bilayer films. The Z-scale ranges are 50 nm for the topography and 50 mV for the surface potential. (Reprinted with permission from Sensors and Actuators A Physical, Layer-by-layer self-assembled conductive thin films for MEMS applications byB. Bush, G. Xu, C. Carraroand R. Maboudian, 126, 1, 194—200. Copyright (2006) Elsevier Ltd)...

E.W.H. lager, E. Smela, and O. Inganas, On-chip microelectrodes for electrochemistry with moveable PPy bilayer actuators as working electrodes. Sens. Actuat. B Chem., 56(1-2), 73-78 (1999). 

The first actuators described for conducting polymers in the early 1990s were bilayer or bending-beam stmctures in which a polymer film on a thin conductor would bend to well... 

Figure 15.1 Conducting-polymer actuation based upon bending of a bilayer or trIlayer actuator in which S-SO-jim-thick polymer layers are typically grown on a metal-coated Inert support the linear stretching of a free-standing film, of several mm to cm in length and the out-of-plane actuation of conducting-polymer films...

Figure 15.7 SEM images (A) regular PPy and (B) templated PPy. (Reprinted with permission from Synthetic Metals, Templated polypyrrole electro-polymerization Self-assembled bundles of bilayer membranes of amphiphiles and their actuation behavior by K. Kagawa, P. Qian, A. Tanaka and T. M. Swager, 157, 18-20, 733-738. Copyright (2007) Elsevier Ltd)...

M. Christophersen, B. Shapiro, and E. Smela, Characterization and modeling of PPy bilayer microactuators. Part 1. Curvature, Sens. Actuators, B, B115 (2), 596-609(2006). 

Polymer composite actuators with a bilayer structure of different coefficients of thermal expansion (CTE) can generate bending displacement. When one side of the film is introduced with conductive fillers, the actuator can be electrothermally driven. PDMS/CNT composite was reported to be driven by the thermal expansion of the PDMS with CNTs as... 

FIGURE 11.21 Schematic showing the bilayer actuator design, wherein one layer in the device contracts or expands... 

J.C. Vidal, E. Garda, and J.R. Castillo. 1999. In situ preparation of overoxidized PPy/oPPD bilayer biosensors for the determination of glucose and cholesterol in serum. Sens Actuators B Chem 57 (1-3) 219. 

Pettersson et al. [139] fabricated a valve based on polypyrrole bending bilayers attached to rigid polymer plates. They fabricated the actuators on a flat surface, and then bonded that to a polymer cover with the fluid channels. Fluid flow was reduced when the plates were rotated perpendicular to the surface so that they blocked the channel. A similar device has been developed to operate a flap that opens and closes the cover on a microvial for cell clinic processes [140-142]. 

The electrochemical synthesis of the films of conducting polymers, and the electrochemical actuation, are suitable for the construction of elegant and imaginative microdevices and microtools bilayers by using microelectronic technologies [110-121]. 

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