Two percolation thresholds and remarkably high dielectric permittivity in pristine carbon nanotube/elastomer composites

Khurram Shehzad,Zhi-Min Dang,Kashif Nadeem,Nasir Said Khisro,Shang-Hong Yao,Muhammad Mumtaz,Yi Xiao-Hong,You Zeng,Ayaz Ali Hakro

doi:10.1007/s13204-015-0403-0

Abstract

Pristine carbon nanotube (CNT)/elastomer composites were fabricated using pristine multi-walled carbon nanotubes and a thermoplastic elastomer. These composites exhibited a unique phenomenon of two electrical percolation thresholds that invoked very high dielectric values for the resulting composites. The first percolation was associated with a relatively low dielectric constant value of about 100, while in the vicinity of the second percolation threshold a very high dielectric constant value of 8,000 was achieved. The presence of two percolation thresholds was attributed to the unique distribution patterns of CNTs that ensued in a CNT/elastomer composite system with unique electrical properties.

Highlights

Dielectric elastomers (DEs), due to their large-strain actuation under the application of a high electric field or to convert mechanical energy into electricity, have found a wide range of applications, such as refreshable braille displays (Niu et al 2012; Yu et al 2009), tunable lenses (Carpi et al 2011), cell stretchers (Akbari and Shea 2012), soft robots (Pei et al 2003) and buoy generators (Chiba et al 2008)
The presence of two percolation thresholds was attributed to the unique distribution patterns of carbon nanotube (CNT) that ensued in a CNT/elastomer composite system with unique electrical properties
This sudden and extraordinary rise in dielectric permittivity values of the composites is the result of interfacial polarization at the interface between elastomer and CNTs caused by the presence of a large number of micro-capacitor structures formed between two neighboring CNTs separated by an insulating matrix

Summary

Introduction

Dielectric elastomers (DEs), due to their large-strain actuation under the application of a high electric field or to convert mechanical energy into electricity, have found a wide range of applications, such as refreshable braille displays (Niu et al 2012; Yu et al 2009), tunable lenses (Carpi et al 2011), cell stretchers (Akbari and Shea 2012), soft robots (Pei et al 2003) and buoy generators (Chiba et al 2008). These composites exhibited a unique phenomenon of two electrical percolation thresholds that invoked very high dielectric values for the resulting composites. The presence of two percolation thresholds was attributed to the unique distribution patterns of CNTs that ensued in a CNT/elastomer composite system with unique electrical properties.

Results

Conclusion