Bio-Inspired, Moisture-Powered Hybrid Carbon Nanotube Yarn Muscles


Hygromorph artificial muscles are attractive as self-powered actuators driven by moisture from the ambient environment. Previously reported hygromorph muscles have been largely limited to bending or torsional motions or as tensile actuators with low work and energy densities. Herein, we developed a hybrid yarn artificial muscle with a unique coiled and wrinkled structure, which can be actuated by either changing relative humidity or contact with water. The muscle provides a large tensile stroke (up to 78%) and a high maximum gravimetric work capacity during contraction (2.17 kJ kg⁻¹), 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. We demonstrate an automatic ventilation system that is operated by the tensile actuation of the hybrid muscles caused by dew condensing on the hybrid yarn. This self-powered humidity-controlled ventilation system could be adapted to automatically control the desired relative humidity of an enclosed space.


Includes supplementary material


Materials science, Nanotechnology, Carbon nanotubes

Creative Research Initiative Center for Self-powered Actuation and the Korea-US Air Force Cooperation Program Grant (no. 2013K1A3A1A32035592); Air Force Office of Scientific Research (grant nos. FA9550-15-1-0089, FA2386-13-1- 4119); Robert A. Welch Foundation grant (no. AT-0029). Additional support was from the Australian Research Council Discovery Grant (DP110101073).


CC BY 4.0 (Attribution), ©2016 The Authors. All Rights Reserved.