Piezoelectric and Dielectric Characterization of MWCNT-Based Nanocomposite Flexible Films

S Banerjee,W Du,U Sundar,K A Cook-Chennault

doi:10.1155/2018/6939621

S Banerjee, W Du + Show 2 more

Open Access

https://doi.org/10.1155/2018/6939621

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Abstract

PZT-epoxy-multiwalled carbon nanotube (MWCNT) flexible thick film actuators were fabricated using a sol-gel and spin coat and deposition process. Films were characterized in terms of their piezoelectric and dielectric properties as a function of MWCNT volume fraction and polarization process. Correlations between surface treatment of the MWCNTs and composite performance were made. The surface morphology and filler distribution were observed with the aid of SEM and TEM images. The volume fraction of PZT was held constant at 30%, and the volume fraction of MWCNTs varied from 1% to 10%. Two forms of dielectric polarization were compared. Corona discharge polarization induced enhanced piezoelectric and dielectric properties by a factor of 10 in comparison to the parallel-plate contact method (piezoelectric strain coefficient and dielectric constant were 0.59 pC/N and 61.81, respectively, for the parallel-plate contact method and 9.22 pC/N and 103.59 for the corona polarization method, respectively). The percolation threshold range was observed to occur at a MWCNT volume fraction range between 5% and 6%.

Highlights

The appropriate sonication time for the surface treatment of the multiwalled carbon nanotube (MWCNT) in ethanol was determined by examining the average particle size and separation of particles using scanning electron microscopy (SEM) micrograph images and transmission electron microscopy (TEM) images
MWCNTs that were produced by arc discharge cathode deposition were ultrasonicated in 40 ml of ethanol for time intervals equal to 30 minutes, 2 hours, 3 hours, 4 hours, and 8 hours
The surface-treated MWCNTs were incorporated into 0-3-0 composite films having 3%, 6%, and 9% volume fraction of MWCNTs

Summary

Introduction

Piezoelectric materials are used as sensors, actuators, and transducers for many applications such as quality assurance [1, 2], process control [3,4,5], industrial and automotive systems [6,7,8,9], medical diagnostics [10, 11], aviation and structural health monitoring [12,13,14,15], biologically engineered scaffolds [16], and embedded passive devices in consumer electronics [17,18,19]. The brittle nature of homogenous ceramic piezoelectric materials limits their operational strains (~8 × 10−6 to 6 × 10−4) [20,21,22], cycle life when subjected to high strain/deformation conditions [23], and ability to be formed into synclastic and complex forms. These challenges often restrict the use of these materials in advanced applications that require sensors that are electromechanically tuned to host structures, while maintaining high sensitivity and reliability over wide frequency ranges. The mechanical, electrical, and acoustic properties of these materials can be tailored according to the nature of application as a function of composition of the composite material [48,49,50,51]

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