Simple and strong: twisted silver painted nylon artificial muscle actuated by Joule heating

Authors

Seyed M. Mirvakili, University of British Columbia
Ali Rafie Ravandi, University of British Columbia
Ian W. Hunter, Massachusetts Institute of Technology
Carter Haines, University of Texas at Dallas
Na Li, University of Texas at Dallas
Javad Foroughi, University of WollongongFollow
Sina Naficy, University of WollongongFollow
Geoffrey M. Spinks, University of WollongongFollow
Ray Baughman, University of Texas at DallasFollow
John Madden, University of British Columbia

RIS ID

89061

Publication Details

Mirvakili, S. M., Ravandi, A., Hunter, I. W., Haines, C. S., Li, N., Foroughi, J., Naficy, S., Spinks, G. M., Baughman, R. H. & Madden, J. D. W. (2014). Simple and strong: twisted silver painted nylon artificial muscle actuated by Joule heating. Proceedings of SPIE: Electroactive Polymer Actuators and Devices (EAPAD) (pp. 90560I-1-90560I-10). United States: SPIE.

Abstract

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-3 (528 J kg-1) and 1.1 kW kg-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.