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New electromechanical transducers with high energy output, high strains, high mechanical compliance, lightweight, damage-tolerance and low cost can enable needed advances in a variety of applications, such as robotics, automation and biomedical devices. The perceived need for improved transducer performance, which has progressively emerged in the last few decades, has drawn considerable efforts for the development of devices relying on materials with intrinsic transduction properties. These materials, often termed " smart " or " intelligent " , include improved piezoelectrics and magnetostrictive or shape-memory materials. While these technologies have addressed niche applications and continue to make incremental improvements, newer emerging electromechanical transduction technologies, based on so-called electroactive polymers (EAP), have gained a considerable attention. EAP offer the potential for performance exceeding other smart materials, while retaining the cost and versatility inherent in polymer materials. EAP are currently being developed and significantly studied as possible " artificial muscles " , i.e. functional surrogates of natural muscles, aimed at mimicking performances of biological actuation machines.Within the EAP family, a specific class of materials, known as " dielectric elastomers " , is drawing particular interest at present, because of its already demonstrated good overall performance, as well as its simplicity of structure and robustness due to the use of stable and commercially available polymer materials. Dielectric elastomer transducers are rapidly emerging as high-performance " pseudo-muscular " actuators, useful for different kinds of tasks. Further, in addition to actuation, dielectric elastomers have also been shown to offer unique possibilities for improved generator and sensing devices.Dielectric elastomer technology was introduced during late 1990s, pioneered by SRI International. While encouraging results have already been achieved, dielectric elastomers are quite new and are still being explored extensively. Dielectric elastomer transduction is enabling an enormous range of new applications that were precluded by any other EAP or smart-material technology until a few years ago.With such a great potential, it is no surprise that research efforts focused on dielectric elastomers are growing rapidly. This is demonstrated by the increasing number of related publications in scientific journals, conferences and workshops, as well as the academic research projects and industrial contracts. Furthermore, while the technology is still new and growing, the technical maturity achieved so far has led to a new company that is focused exclusively on commercially exploiting the potential of dielectric elastomers. This company, Artificial Muscle, Inc., was founded in 2004.This book intends to provide a comprehensive and updated insight on dielectric elastomer transduction, by covering all its fundamental aspects. The book is organized in five main sections, dealing with transduction principle...

Electroactive polymer (EAP) actuators are electrically responsive materials that have several characteristics in common with natural muscles. Thus, they are being studied as 'artificial muscles' for a variety of biomimetic motion applications. EAP materials are commonly classified into two major families: ionic EAPs, activated by an electrically induced transport of ions and/or solvent, and electronic EAPs, activated by electrostatic forces. Although several EAP materials and their properties have been known for many decades, they have found very limited applications. Such a trend has changed recently as a result of an effective synergy of at least three main factors: key scientific breakthroughs being achieved in some of the existing EAP technologies; unprecedented electromechanical properties being discovered in materials previously developed for different purposes; and higher concentration of efforts for industrial exploitation. As an outcome, after several years of basic research, today the EAP field is just starting to undergo transition from academia into commercialization, with significant investments from large companies. This paper presents a brief overview on the full range of EAP actuator types and the most significant areas of interest for applications. It is hoped that this overview can instruct the reader on how EAPs can enable bioinspired motion systems.

A soft polymer actuator has been constructed based on the volume change of a conducting polymer. The linear expansion (12 % at a load of 0.5 MPa) is the highest yet reported for a centimeter‐scale conducting polymer actuator. This is achieved by controlling the structure on several length scales: Choice of molecular structure, synthesis from a structured medium, and forming the polymer actuator on a compliant, microstructured gold electrode.

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The influence of stoichiometry on the elastic modulus of eight-functional end-linked poly-(dimethylsiloxane) (PDMS) networks was investigated by extensional rheometry with extensions up to more than 100%, and the stress-strain relation was found to be almost linearsa characteristic property for a network structure with an eight-functional cross-linker. The experimental data were compared to a stochastic model taking into account entanglements and to Monte Carlo simulations. The Mooney-Rivlin model was furthermore used to fit the data, and the dependency of C 1 and C2 parameters on the stoichiometric ratio was investigated in order to clarify especially the influence of trapped entanglements acting either as chemical cross-links or as sliding links. It was found that including a locking factor dividing trapped entanglements into locked entanglements and slip-links could explain our data obtained for the Mooney-Rivlin constants. It was furthermore found that trapped entanglements dominate when there is an excess of cross-linker, ensuring that all long difunctional DMS chains are bound to the infinite network in both ends.

 Users may download and print one copy of any publication from the public portal for the purpose of private study or research.  You may not further distribute the material or use it for any profit-making activity or commercial gain  You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.