Soft but Powerful Artificial Muscles Based on 3D Graphene–CNT–Ni Heteronanostructures

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 13; no. 31
• Main Authors: Kim, Jaehwan, Bae, Seok‐Hu, Kotal, Moumita, Stalbaum, Tyler, Kim, Kwang J., Oh, Il‐Kwon
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.08.2017
• Subjects: Actuation; Actuators; Artificial muscles; Artificial Organs; Bioengineering - methods; carbon nanotube; Carbon nanotubes; Deformation; Durability; Electric Conductivity; Electric contacts; Electrical resistivity; Electrodes; Graphene; Graphite - chemistry; Hardness - physiology; heteronanostructure; Humans; Ion currents; Ionic liquids; ionic polymer; Ions; Modulus of elasticity; Nanostructures - chemistry; Nanotechnology; Nanotubes, Carbon - chemistry; Nickel; Nickel - chemistry; Performance enhancement; Prostheses and Implants; soft actuator; Tensile strength; Tissue Scaffolds - chemistry; Torsion, Mechanical; carbon nanotube; ionic polymer; heteronanostructure; soft actuator; graphene
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201701314

Bioinspired soft ionic actuators, which exhibit large strain and high durability under low input voltages, are regarded as prospective candidates for future soft electronics. However, due to the intrinsic drawback of weak blocking force, the feasible applications of soft ionic actuators are limited until now. An electroactive artificial muscle electro‐chemomechanically reinforced with 3D graphene–carbon nanotube–nickel heteronanostructures (G–CNT–Ni) to improve blocking force and bending deformation of the ionic actuators is demonstrated. The G–CNT–Ni heteronanostructure, which provides an electrically conductive 3D network and sufficient contact area with mobile ions in the polymer electrolyte, is embedded as a nanofiller in both ionic polymer and conductive electrodes of the ionic actuators. An ionic exchangeable composite membrane consisting of Nafion, G–CNT–Ni and ionic liquid (IL) shows improved tensile modulus and strength of up to 166% and 98%, respectively, and increased ionic conductivity of 0.254 S m−1. The ionic actuator exhibits enhanced actuation performances including three times larger bending deformation, 2.37 times higher blocking force, and 4 h durability. The electroactive artificial muscle electro‐chemomechanically reinforced with 3D G–CNT–Ni heteronanostructures offers improvements over current soft ionic actuator technologies and can advance the practical engineering applications. Soft but strong electroactive polymer actuators are developed utilizing 3D graphene–carbon nanotube–nickel heteronanostructures. The developed artificial muscles exhibit large bending deformations and high blocking forces with high durability for long‐term operation, owing to the electro‐chemomechanical reinforcement of 3D graphene–carbon nanotube–nickel heteronanostructures.