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Dielectric Elastomers (dielectric + elastomer)

Distribution by Scientific Domains
Polymers and Materials Science100%

Terms modified by Dielectric Elastomers

  • dielectric elastomer actuator
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    Selected Abstracts

    Silicone,Poly(hexylthiophene) Blends as Elastomers with Enhanced Electromechanical Transduction Properties,

    ADVANCED FUNCTIONAL MATERIALS, Issue 2 2008
    F. Carpi
    Abstract Dielectric elastomers are progressively emerging as one of the best-performing classes of electroactive polymers for electromechanical transduction. They are used for actuation devices driven by the so-called Maxwell stress effect. At present, the need for high-driving electric fields limits the use of these transduction materials in some areas of potential application, especially in the case of biomedical disciplines. A reduction of the driving fields may be achieved with new elastomers offering intrinsically superior electromechanical properties. So far, most attempts in this direction have been focused on the development of composites between elastomer matrixes and high-permittivity ceramic fillers, yielding limited results. In this work, a different approach was adopted for increasing the electromechanical response of a common type of dielectric elastomer. The technique consisted in blending, rather than loading, the elastomer (poly(dimethylsiloxane)) with a highly polarizable conjugated polymer (undoped poly(3-hexylthiophene)). The resulting material was characterised by dielectric spectroscopy, scanning electron microscopy, tensile mechanical analysis, and electromechanical transduction tests. Very low percentages (1,6 wt %) of poly(3-hexylthiophene) yielded both an increase of the relative dielectric permittivity and an unexpected reduction of the tensile elastic modulus. Both these factors synergetically contributed to a remarkable increase of the electromechanical response, which reached a maximum at 1 wt % content of conjugated polymer. Estimations based on a simple linear model were compared with the experimental electromechanical data and a good agreement was found up to 1 wt %. This approach may lead to the development of new types of materials suitable for several types of applications requiring elastomers with improved electromechanical properties. [source]

    Fault-Tolerant Dielectric Elastomer Actuators using Single-Walled Carbon Nanotube Electrodes,

    ADVANCED MATERIALS, Issue 3 2008
    W. Yuan
    Fault-tolerant actuators. Single-walled carbon nanotubes were studied as new compliant electrodes for dielectric elastomers. The spray-coated SWNT electrodes drive electromechanical strains greater than 200,%. When a fault is present due to pin puncture or internal defect in the elastomer films, dielectric breakdown causes localized self-clearing of the SWNT electrodes and isolation of the fault. The increased fault tolerance may enhance the actuation reliability of dielectric elastomers actuators. [source]

    Millimetre-scale bubble-like dielectric elastomer actuators

    POLYMER INTERNATIONAL, Issue 3 2010
    Federico Carpi
    Abstract Hydrostatic coupling has recently been reported as a means to improve the versatility and safety of electromechanical actuators based on dielectric elastomers (DEs). Hydrostatically coupled DE actuators rely on an incompressible fluid that mechanically couples a DE-based active part to a passive part interfaced to the load. The work reported here was aimed at developing millimetre-scale bubble-like versions of such transducers. Silicone-made oil-filled actuators were manufactured as both single units and arrays of parallel elements. Bubbles had a base diameter of 6 mm and were driven up to a voltage of 2.25 kV, applied across a silicone film with a thickness of 42 µm. Active relative displacements and stresses up to 18% and 2.2 kPa, respectively, were recorded with static driving. Dynamic investigations reported a ,3 dB bandwidth of the order of 100 Hz and a resonance frequency of about 250 Hz. Millimetre-scale hydrostatically coupled DE actuators might play a useful role in several fields of application. Among them, we are currently exploring novel tactile displays and cutaneous stimulators, made of wearable, distributed and flexible devices. Although further miniaturization is required for high-resolution uses, this technology holds promise to properly combine performance with safe and compliant interfaces with users, low specific weight, no acoustic noise and low cost. Copyright © 2009 Society of Chemical Industry [source]