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The effects of layer thickness and stiffness on multilayer bending actuator performance were investigated with an analytical mechanical model. Performance was evaluated in terms of curvature, blocked force, and work. Multilayer device designs corresponding to dielectric elastomer actuator, ionic polymer metal composite, and conjugated polymer structures were examined. Normalized plots of the performance metrics as functions of relative layer thickness and stiffness are presented that should allow initial, starting-point estimates for designs for particular applications. The results show that to achieve high curvature, layer thickness and stiffness may need to be set above or below particular bounds, or varied together, depending on the device configuration; often there is a broad plateau of combinations that work equally well. There is a conflict between achieving high bending and high force: the former requires the device to behave as much as possible like a simple bilayer with optimal ratios of thickness and modulus, while the latter requires thicker layers and shows little dependence on their moduli. Finally, to maximize work there are areas in the thickness-modulus plane that should be avoided, these areas varying with the configuration in sometimes surprising ways.

All-polymer dielectric elastomer actuators have been manufactured using a micro-molding fabrication process. The actuators are multilayer beams made of three conductive and two dielectric elastomer layers. By applying an electrical potential between two of the neighboring conductive electrodes, a stress is generated, which leads to an asymmetric axial strain and, therefore, bending. Bidirectional actuation is achieved by changing the pair of electrodes across which the potential is applied. A 100??m wide, 40??m thick, and 1000??m long actuator demonstrated tip displacement as high as 318??m at 1.1?kV with an electrical power consumption of 10??W. Experimental results validate a two-dimensional ANSYS model that is also used to explore the effects of further decreasing layer thickness and relative electrode thickness on DEA performance.

Meandering beams, crenellated surfaces, and zigzag-shaped electrodes are employed as compliant elements in microscale applications ranging from springs attached to proof masses in microelectromechanical systems (MEMS) to stretchable electrodes in flexible electronics and dielectric elastomer actuators. An understanding of how the meander shape affects the stiffness of these structures would permit preliminary design without the necessity of fabricating or running simulations on each case. In this paper, we present general guidelines for designing meandering cantilevers, showing how the amplitude, angle, length, and thickness affect both the axial and bending stiffnesses. Simple analytical expressions are derived, and the results are compared with those from numerical simulations and experimental measurements. The more complex case of a stiff thin film overlying a crenellated elastomer is also simulated.

PDMS films of 10 μm thickness can be patterned within 30 min by combining dry etching to achieve substantially vertical sidewalls with wet etching to achieve high etch rates and to protect the underlying substrate from attack. Dry etching alone would have taken 5 h, and wet etching alone would produce severe undercutting. In addition, using either technique alone produces undesirable surface morphologies. The mask used during etching is critical to a successful patterning outcome. E-beam evaporated Al was found to work well, adhering strongly to oxygen-plasma-treated PDMS and holding up well during both dry and wet etching. To prevent wrinkling of the PDMS, a fast deposition rate should be used. (Some figures in this article are in colour only in the electronic version)