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Proceedings Paper

Strain-dependent and hysteretic resistance of stretchable carbon nanotube networks (Conference Presentation)
Author(s): Lihua Jin; Alex Chortos; Christian Linder; Zhenan Bao; Wei Cai

Paper Abstract

The increasing demands of human-machine integration require stretchable electronic devices. Percolating networks of carbon nanotubes (CNTs) have potential to work as stretchable electrodes and semiconductors, since CNTs can reorient and slide under large deformation. In this work, we investigate the effect of cyclic loadings on the resistance and morphology of stretchable CNT electrodes, by combining experiment, coarse grained molecular static (CGMS) simulation, and analytical modeling. Experimentally, a CNT electrode spray-coated on the surface of a stretchable substrate is subject to cyclic stretches with the maximal strain sequentially increasing. The resistance of the electrode in both stretching and transverse directions increases during the loading, while it remains almost a constant during the unloading, forming a hysteresis between the loading and unloading. To understand the strain-dependent and hysteretic resistance of stretchable CNT electrodes, we have developed a CGMS method to simulate the morphological change of CNT networks under cyclic loadings. Then we calculate the evolution of the resistance for different CNT configurations, by modeling a network of nanotube resistances and contact resistances. We find that during stretching, the CNTs reorient to the stretching direction. As the strain increases, the nanotubes slide between each other, and the resistance of the network increases. During the unloading, the CNTs buckle due to the compression, and the resistance of the network remains almost a constant. Based on this understanding, we have further developed an analytical model to describe the evolution of the resistance of CNT electrodes under arbitrary loadings. This combined approach enables us to design stretchable CNT devices with optimized properties.

Paper Details

Date Published: 10 May 2017
PDF: 1 pages
Proc. SPIE 10165, Behavior and Mechanics of Multifunctional Materials and Composites 2017, 101650S (10 May 2017); doi: 10.1117/12.2260409
Show Author Affiliations
Lihua Jin, Univ. of California, Los Angeles (United States)
Alex Chortos, Stanford Univ. (United States)
Christian Linder, Stanford Univ. (United States)
Zhenan Bao, Stanford Univ. (United States)
Wei Cai, Stanford Univ. (United States)


Published in SPIE Proceedings Vol. 10165:
Behavior and Mechanics of Multifunctional Materials and Composites 2017
Nakhiah C. Goulbourne, Editor(s)

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