Hierarchical Graphene‐Based Films with Dynamic Self‐Stiffening for Biomimetic Artificial Muscle. (16th August 2016)

• Record Type: Journal Article
• Authors: Dai, Zhaohe; Wang, Yanlei; Liu, Luqi; Liu, Xuelu; Tan, PingHeng; Xu, Zhiping; Kuang, Jun; Liu, Qing; Lou, Jun; Zhang, Zhong
• Is Part Of: Advanced functional materials. Volume 26:Number 38(2016)
• Page Start: 7003
• Page End: 7010
• Publication Date: 2016-08-16
• Subjects: graphene oxides -- mechanical properties -- microstructure evolution -- molecular dynamics simulations -- self‐stiffening; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201503917
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract : Biological tissues such as muscle cells can adapt their structural and mechanical response upon external mechanical stimuli. Conversely, artificial muscles, intended to reproduce the salient functional features of biological muscles, usually undergo mechanical fatigue when subjected to dynamic stress. Besides passively improving the resilience to dynamic loads, here, it is reported that macroscopic films based on graphene and its chemical derivate exhibit an increase in modulus by up to 84% after subjected to a low‐amplitude (0.1%) dynamic tension. Through a combination of experimental testing and molecular dynamics simulations, the unique self‐stiffening behavior is attributed to the straightening and reorientation of graphene sheets and is further tuned through tailoring interlayer adhesion. Meanwhile, artificial muscles based on graphene films are designed and interestingly improved stiffness of our muscle materials after "training" are demonstrated. These results help to harness the stiffening mechanism and can be useful for the development of adaptable structural materials for biomechanical applications. Abstract : Macroscopic films based on hierarchical graphene and its chemical derivate possessing tunable interfacial features are synthesized. This paper describes the self‐stiffening responses of these macroscopic materials to dynamic tension and demonstrates an as high as 84% increase in Young's modulus. Systematic mechanical tests, microstructural characterizations, molecular dynamics simulations, and model analysis are performed to clarify the unusual self‐stiffening mechanism. By utilizing these graphene‐based films, artificial muscles with dynamic self‐stiffening behavior are designed.