Electromechanical actuators dielectric elastomers

Carpi, F., Chiarelli, P., Mazzoldi, A., and De Rossi, D., Electromechanical characterisation of dielectric elastomer planar actuators Comparative evaluation of different electrode materials and different counterloads, Sensors Actuators, A107, 85, 2003. 

Carpi, F. and Rossi, D.D., Dielectric elastomer cylindrical actuators Electromechanical modeling and experimental evaluation, Mater. Set Eng., C24, 555, 2004. 

Wissler M, Mazza E (2007) Electromechanical coupling in dielectric elastomer actuators. 

Carpi F, De Rossi D (2005) Improvement of electromechanical actuating performances of a silicone dielectric elastomer by dispersion of titanium dioxide powder. IEEE Trans Dielectr Electr Insul 12 835... 

Carpi F, De Rossi D (2004) Dielectric elastomer cylindrical actuators electromechanical modeling and experimental evaluation. Mater Sci Eng C 24 555... 

Koh et al. [6] have rigorously modeled the electromechanics of this interaction for the simplified case of uniform biaxial stretching of an incompressible polymer film including many important effects such as the nonlinear stiffness behavior of the polymer film and the variation in breakdown field with the state of strain. With regard to the latter effect, Pelrine et al. [5] showed the dramatic effect of prestrain on the performance of dielectric elastomers (specifically silicones and acrylics) as actuators. We would expect the same breakdown enhancement effects to be involved with regard to power generation. There are many additional effects that may be important, such as electrical and mechanical loss mechanisms, interaction with the environment or circuits, frequency, and temperature-dependent effects on material parameters. The analysis by Koh provides the state equations... 

Carpi F, DeRossi D, Kombluh R, Pelrine R, Somer-Larsen P (2008) Dielectric elastomers as electromechanical transducers, fundamentals, materials, devices, models and applications of an emerging electroactive polymer technology. Elsevier Press, Amsterdam Chapter 7 Benslimane M, Kiil H-E, Tryson MJ (2010) Electromechanical properties of novel large strain PolyPower film and laminate components for DEAP actuator and sensor applications. Proc SPIE 7642 764231... 

Gallone G, Galantini F, Carpi F (2010) Perspectives for new dielectric elastomers with improved electromechanical actuation performance composites versus blends. Polym Int 59 400-406. doi 10.1002/pi.2765... 

Carpi F, Chiarelli P, Mazzoldi A, De Rossi D (2003) Electromechanical characterization of dielectric elastomer planar actuators comparative evaluation of different electrode materials and different counterloads. Sens Actuators A Phys 107(l) 85-95. doi 10.1016/S0924.4247 (03)00257-7... 

Tangborihoon N, Datsanae S, Onthong A, Kunanuruksapong R, Sirivat A (2013) Electromechanical responses of dielectric elastomer composite actuators based on natural rabher and alumina. J Elastom Plast 45 143... 

TABLE 16.2 Comparison between Two Mechanical Properties of Different Actuating Materials Skeletal Muscles, Thermomechanical (Thermal Liquid Crystals and Thermal Shape Memory Alloys), Electrochemomechanical (Conducting Polymers and Carbon Nanotubes) and Electromechanical (Ionic Polymer Metal Composites, Field Driven Liquid Crystal Elastomers, Dielectric Elastomers)... 

On the contrary, dielectric elastomer actuators are characterized by the necessity of high driving voltages, while offering interesting electromechanical performances, consisting of large, fast and stable deformations at moderate stresses. 

Many fundamental studies have been carried out to fully understand the nature of the positive effect of prestraining on the actuation performance of dielectric elastomers. The observed improvements have been mainly attributed to the enhancement of the actuator s stability. The main electromechanical instability in the dielectric elastomers is called the pull-in... 

Dielectric elastomer transducers are based on the electromechanical response of an elastomeric dielectric film with comphant electrodes on each surface. These transducers may be actuators, generators, or sensors. In aU cases, the basic stmcture is the same. 

PeMne, R. and Kornbluh, R. Introduction History of dielectric elastomer actuators in Dielectric Elastomers as Electromechanical Transducers (eds Carpi, F., DeRossi, D., Kornbluh, et oL), Elsevier, Oxford, UK, 2008. 

In any case, polyurethane dielectric elastomers have continued to be studied in the last decade, particularly with regard to the possibility of increasing their actuation performance. It is well known that both dielectric and mechanical properties are key parameters governing the electromechanical response of any dielectric elastomer, which can be in principle improved by an increase of the dielectric constant and by a decrease of the elastic modulus. In order to increase the dielectric permittivity of a polymer elastomeric matrix, various methods are available (Carpi et al. 2008), such as making composites or blends with highly polarizable phases. Table 1 constitutes a non-exhaustive list of works fi-om the literature, mostly relying on such methods for improving the performance of polyurethane dielectric elastomers. The studies are classified in terms of system complexity and component materials. 

Zhang H, During L, Kovacs G et al (2010) Interpenetrating polymer networks based on acrylic elastomers and plasticizers with improved actuation temperature range. Polym Int 59 384-390 Zhao X, Suo Z (2007) Method to analyze electromechanical stability of dielectric elastomers. Appl Phys Lett 91 061921... 

The unique advantages of dielectric elastomers have stimulated a great number of apphcations which can be categorized into actuators, energy harvesters, and sensors. This chapter presents multiple electromechanical transduction systems including biologically inspired robotics, tactile feedback and displays, tunable optics, fluid control and microfluidics, capacitive sensors, and energy harvesters. 

---