Simple and strong: twisted silver painted nylon artificial muscle actuated by Joule heating
Author(s)Mirvakili, Seyed Mohammad; Rafie Ravandi, Ali; Haines, Carter S.; Li, Na; Foroughi, Javad; Naficy, Sina; Spinks, Geoffrey M.; Baughman, Ray H.; Madden, John D. W.; Hunter, Ian; ... Show more Show less
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Highly oriented nylon and polyethylene fibres shrink in length when heated and expand in diameter. By twisting and then coiling monofilaments of these materials to form helical springs, the anisotropic thermal expansion has recently been shown to enable tensile actuation of up to 49% upon heating. Joule heating, by passing a current through a conductive coating on the surface of the filament, is a convenient method of controlling actuation. In previously reported work this has been done using highly flexible carbon nanotube sheets or commercially available silver coated fibres. In this work silver paint is used as the Joule heating element at the surface of the muscle. Up to 29% linear actuation is observed with energy and power densities reaching 840 kJ m[superscript -3] (528 J kg[superscript -1]) and 1.1 kW kg[superscript -1] (operating at 0.1 Hz, 4% strain, 1.4 kg load). This simple coating method is readily accessible and can be applied to any polymer filament. Effective use of this technique relies on uniform coating to avoid temperature gradients.
DepartmentMassachusetts Institute of Technology. BioInstrumentation Laboratory; Massachusetts Institute of Technology. Department of Mechanical Engineering
Proceedings of SPIE--the International Society for Optical Engineering
Mirvakili, Seyed M., Ali Rafie Ravandi, Ian W. Hunter, Carter S. Haines, Na Li, Javad Foroughi, Sina Naficy, Geoffrey M. Spinks, Ray H. Baughman, and John D. W. Madden. “Simple and Strong: Twisted Silver Painted Nylon Artificial Muscle Actuated by Joule Heating.” Edited by Yoseph Bar-Cohen. Electroactive Polymer Actuators and Devices (EAPAD) 2014 (March 8, 2014). © 2014 SPIE
Final published version