title: Hybrid carbon nanotube yarn artificial muscle inspired by spider dragline silk.
abstract: Torsional artificial muscles generating fast, large-angle rotation have been recently demonstrated, which exploit the helical configuration of twist-spun carbon nanotube yarns. These wax-infiltrated, electrothermally powered artificial muscles are torsionally underdamped, thereby experiencing dynamic oscillations that complicate positional control. Here, using the strategy spiders deploy to eliminate uncontrolled spinning at the end of dragline silk, we have developed ultrafast hybrid carbon nanotube yarn muscles that generated a 9,800 r.p.m. rotation without noticeable oscillation. A high-loss viscoelastic material, comprising paraffin wax and polystyrene-poly(ethylene-butylene)-polystyrene copolymer, was used as yarn guest to give an overdamped dynamic response. Using more than 10-fold decrease in mechanical stabilization time, compared with previous nanotube yarn torsional muscles, dynamic mirror positioning that is both fast and accurate is demonstrated. Scalability to provide constant volumetric torsional work capacity is demonstrated over a 10-fold change in yarn cross-sectional area, which is important for upscaled applications.
authors.affiliation: Center for Bio-Artificial Muscle and Department of Biomedical Engineering, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Kyoung-Yong
authors.initials: KY
authors.lastname: Chun
authors.affiliation: Center for Bio-Artificial Muscle and Department of Biomedical Engineering, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Shi
authors.initials: S
authors.lastname: Hyeong Kim
authors.affiliation: Center for Bio-Artificial Muscle and Department of Biomedical Engineering, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Min
authors.initials: M
authors.lastname: Kyoon Shin
authors.affiliation: Center for Bio-Artificial Muscle and Department of Biomedical Engineering, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Cheong
authors.initials: C
authors.lastname: Hoon Kwon
authors.affiliation: Center for Bio-Artificial Muscle and Department of Biomedical Engineering, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Jihwang
authors.initials: J
authors.lastname: Park
authors.affiliation: IT Fusion Technology Research Center and Department of IT Fusion Technology, Chosun University, Gwangju 501-759, South Korea.
authors.forename: Youn
authors.initials: Y
authors.lastname: Tae Kim
authors.affiliation: ARC Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, University of Wollongong, Wollongong, NSW 2522, Australia.
authors.forename: Geoffrey M
authors.initials: GM
authors.lastname: Spinks
authors.affiliation: The Alan G. MacDiarmid NanoTech Institute, University of Texas at Dallas, Richardson, Texas 75083, USA.
authors.forename: Márcio D
authors.initials: MD
authors.lastname: Lima
authors.affiliation: The Alan G. MacDiarmid NanoTech Institute, University of Texas at Dallas, Richardson, Texas 75083, USA.
authors.forename: Carter S
authors.initials: CS
authors.lastname: Haines
authors.affiliation: The Alan G. MacDiarmid NanoTech Institute, University of Texas at Dallas, Richardson, Texas 75083, USA.
authors.forename: Ray H
authors.initials: RH
authors.lastname: Baughman
authors.affiliation: Center for Bio-Artificial Muscle and Department of Biomedical Engineering, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Seon
authors.initials: S
authors.lastname: Jeong Kim
mesh_terms: D000818:Animals; D001187:Artificial Organs; D009132:Muscles; D037742:Nanotubes, Carbon / Q000737:chemistry*; D047011:Silk / Q000737:chemistry*; D013112:Spiders
chemical_list: D037742:Nanotubes, Carbon; D047011:Silk