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Environmentally Powered Yarn Arrays that Sense, Actuate, Harvest, and Store Energy (NBIT III)
Technical Report,14 Aug 2013,13 Aug 2016
UNIVERSITY OF TEXAS AT DALLAS Richardson United States
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In our early NBIT III advance, we used twist insertion and coiling to transform the high strength polymers found in fishing line and sewing thread into large stroke, highly reversible, thermally-powered artificial muscles that 1 generated five times higher gravimetric mechanical power during muscle contraction than the gravimetric power generation capability of a cars combustion engine and 2 functioned as a torsional artificial muscle to rotate a heavy rotor to over 90,000 rpm. By driving this torsional actuation using 19.6C fluctuations in air temperature, we obtained an average output electrical power of 124 W per kg of muscle mass. Our subsequent NBIT III results have expanded our understanding of actuation mechanism, including providing results on the entropy-based mechanocaloric cooling resulting from stretch release and twist de-insertion. A carbon nanotube hybrid muscle that is driven by either fluctuating relative humidity or periodic contact with water was obtained. This bioinspired, muscle provided a giant tensile stroke up to 78 and a giant maximum gravimetric work capacity during contraction 2.17 kJ kg1, which is over 50 times that of the same weight human muscle and 5.5 times higher than for the same weight spider silk, which is the previous record holder for a moisture-driven muscle. Additional work has focused on engineering comfort adjusting clothing textiles that open and close porosity depending upon ambient temperature andor humidity or the existence of sweat.
APPROVED FOR PUBLIC RELEASE