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Papers by Kimberly Cook-chennault

Research paper thumbnail of Investigation of Piezoelectricity and Resistivity of Surface Modified Barium Titanate Nanocomposites

Polymers

Polymer-ceramic nanocomposite piezoelectric and dielectric films are of interest because of their... more Polymer-ceramic nanocomposite piezoelectric and dielectric films are of interest because of their possible application to advanced embedded energy storage devices for printed wired electrical boards. The incompatibility of the two constituent materials; hydrophilic ceramic filler, and hydrophobic epoxy limit the filler concentration, and thus, their piezoelectric properties. This work aims to understand the role of surfactant concentration in establishing meaningful interfacial layers between the epoxy and ceramic filler particles by observing particle surface morphology, piezoelectric strain coefficients, and resistivity spectra. A comprehensive study of nanocomposites, comprising non-treated and surface treated barium titanate (BTO), embedded within an epoxy matrix, was performed. The surface treatments were performed with two types of coupling agents: Ethanol and 3-glycidyloxypropyltrimethoxysilan. The observations of particle agglomeration, piezoelectric strain coefficients, and...

Research paper thumbnail of Influence of Al inclusions and PZT volume fraction on the dielectric and piezoelectric characteristics of three phase PZT-Cement-Al composites

Research paper thumbnail of Influence of Al Particle Size and PZT Volume Fraction on the Dielectric Properties of PZT-Epoxy-Aluminum Composites

Journal of Engineering Materials and Technology

Research paper thumbnail of Multi Walled Carbon Nanotube based Flexible Multi-morph Composite Thick Films with Graphene Electrodes

Science of Advanced Materials

Three-phase, PZT(PbZr0.52Ti0.48O3)-Epoxy- Multi-walled Carbon-Nanotube (MWCNT) flexible films hav... more Three-phase, PZT(PbZr0.52Ti0.48O3)-Epoxy- Multi-walled Carbon-Nanotube (MWCNT) flexible films have been prepared via a combination solvent and spin coating technique. The composite materials were spin coated onto flexible stainless steel substrate, and either graphene or graphene - PMMA films were grown by a chemical vapor deposition process on the other side of the films. The thicknesses of the films were ~ 200 μm. The volume fraction of the MWCNTs was varied from 1% to 6%, while the PZT volume fraction was held constant at 30%. The strain coefficient and capacitance were measured as a function of the MWCNT volume fraction, and were subsequently used to determine the effective dielectric constant of the composite. Samples that incorporated graphene electrodes had higher effective dielectric constants than samples that incorporated graphene-PMMA electrodes and those with no top electrode. For example, the maximum values of effective dielectric constant for the composite films were ~...

Research paper thumbnail of Multi-Walled Carbon-Nanotube Based Flexible Piezoelectric Films with Graphene Monolayers

Energy and Environment Focus, 2013

ABSTRACT Three-phase, PZT(PbZr0.52Ti0.48O3)-Epoxy-Multi-walled Carbon-Nanotube (MWCNT) flexible f... more ABSTRACT Three-phase, PZT(PbZr0.52Ti0.48O3)-Epoxy-Multi-walled Carbon-Nanotube (MWCNT) flexible films have been prepared via a combination solvent and spin coating technique. The composite materials were spin coated onto flexible stainless steel substrate, and either graphene or graphene-PMMA films were grown by a chemical vapor deposition process on the other side of the films. The thicknesses of the films were 200 μm. The volume fraction of the MWCNTs was varied from 1% to 6%, while the PZT volume fraction was held constant at 30%. The strain coefficient and capacitance were measured as a function of the MWCNT volume fraction, and were subsequently used to determine the effective dielectric constant of the composite. Samples that incorporated graphene electrodes had higher effective dielectric constants than samples that incorporated graphene-PMMA electrodes and those with no top electrode. For example, the maximum values of effective dielectric constant for the composite films were ∼4353, ∼1945 and ∼61, for samples having graphene, graphene-PMMA and no electrode respectively. Similarly, composite films with graphene electrodes produced strain coefficients, e.g., d 33 and d 31 that were larger than their counterparts. Sample surface morphology and sample composition were observed using SEM and measured using Raman Spectroscopy respectively. Improved dielectric properties observed for samples with graphene coatings are due to graphene's high carrier mobility and ability to readily conform to the surface of the sample.

Research paper thumbnail of Powering MEMS portable devices—a review of non-regenerative and regenerative power supply systems with special emphasis on piezoelectric energy harvesting systems

Smart Materials and Structures, 2008

Research paper thumbnail of An analytical model for the effective dielectric constant of a 0-3-0 composite

An analytical expression for prediction of the effective dielectric constant of a three phase 0-3... more An analytical expression for prediction of the effective dielectric constant of a three phase 0-3-0 ferroelectric composite is presented. The analytical results are verified with the experimental results from Nan et al. (2002, “Three-Phase Magnetoelectric Composite of Piezoelectric Ceramics, Rare-Earth Iron Alloys, and Polymer,” Appl. Phys. Lett., 81(20), p. 3831). The analytical model is extended to include the shape of a third phase inclusion to examine the influence of the shape (of the inclusion) on the effective dielectric constant of the composite. The dielectric constant increases as much as seven times when the aspect ratio of the conducting inclusion particle is increased from 1 (sphere) to 10 (spheroid). A comparison of the analytical predictions with the experimental values, which indicate that the increase in aspect ratio of the inclusions has a significant effect on the overall dielectric constant of the composite.

Research paper thumbnail of Fabrication of dome-shaped PZT-epoxy actuator using modified solvent and spin coating technique

Journal of Electroceramics, 2013

Research paper thumbnail of An investigation into the influence of electrically conductive particle size on electromechanical coupling and effective dielectric strain coefficients in three phase composite piezoelectric polymers

Composites Part A: Applied Science and Manufacturing, 2012

Research paper thumbnail of Piezoelectric Energy Harvesting: A Green and Clean Alternative for Sustained Power Production

Bulletin of Science, Technology & Society, 2008

Research paper thumbnail of Influence of aluminium inclusions on dielectric properties of three-phase PZT–cement–aluminium composites

Advances in Cement Research, 2014

Research paper thumbnail of Piezoelectric and Dielectric Properties of PZT-Cement-Aluminum Nano-Composites

Research paper thumbnail of Investigation of Piezoelectricity and Resistivity of Surface Modified Barium Titanate Nanocomposites

Polymers

Polymer-ceramic nanocomposite piezoelectric and dielectric films are of interest because of their... more Polymer-ceramic nanocomposite piezoelectric and dielectric films are of interest because of their possible application to advanced embedded energy storage devices for printed wired electrical boards. The incompatibility of the two constituent materials; hydrophilic ceramic filler, and hydrophobic epoxy limit the filler concentration, and thus, their piezoelectric properties. This work aims to understand the role of surfactant concentration in establishing meaningful interfacial layers between the epoxy and ceramic filler particles by observing particle surface morphology, piezoelectric strain coefficients, and resistivity spectra. A comprehensive study of nanocomposites, comprising non-treated and surface treated barium titanate (BTO), embedded within an epoxy matrix, was performed. The surface treatments were performed with two types of coupling agents: Ethanol and 3-glycidyloxypropyltrimethoxysilan. The observations of particle agglomeration, piezoelectric strain coefficients, and...

Research paper thumbnail of Influence of Al inclusions and PZT volume fraction on the dielectric and piezoelectric characteristics of three phase PZT-Cement-Al composites

Research paper thumbnail of Influence of Al Particle Size and PZT Volume Fraction on the Dielectric Properties of PZT-Epoxy-Aluminum Composites

Journal of Engineering Materials and Technology

Research paper thumbnail of Multi Walled Carbon Nanotube based Flexible Multi-morph Composite Thick Films with Graphene Electrodes

Science of Advanced Materials

Three-phase, PZT(PbZr0.52Ti0.48O3)-Epoxy- Multi-walled Carbon-Nanotube (MWCNT) flexible films hav... more Three-phase, PZT(PbZr0.52Ti0.48O3)-Epoxy- Multi-walled Carbon-Nanotube (MWCNT) flexible films have been prepared via a combination solvent and spin coating technique. The composite materials were spin coated onto flexible stainless steel substrate, and either graphene or graphene - PMMA films were grown by a chemical vapor deposition process on the other side of the films. The thicknesses of the films were ~ 200 μm. The volume fraction of the MWCNTs was varied from 1% to 6%, while the PZT volume fraction was held constant at 30%. The strain coefficient and capacitance were measured as a function of the MWCNT volume fraction, and were subsequently used to determine the effective dielectric constant of the composite. Samples that incorporated graphene electrodes had higher effective dielectric constants than samples that incorporated graphene-PMMA electrodes and those with no top electrode. For example, the maximum values of effective dielectric constant for the composite films were ~...

Research paper thumbnail of Multi-Walled Carbon-Nanotube Based Flexible Piezoelectric Films with Graphene Monolayers

Energy and Environment Focus, 2013

ABSTRACT Three-phase, PZT(PbZr0.52Ti0.48O3)-Epoxy-Multi-walled Carbon-Nanotube (MWCNT) flexible f... more ABSTRACT Three-phase, PZT(PbZr0.52Ti0.48O3)-Epoxy-Multi-walled Carbon-Nanotube (MWCNT) flexible films have been prepared via a combination solvent and spin coating technique. The composite materials were spin coated onto flexible stainless steel substrate, and either graphene or graphene-PMMA films were grown by a chemical vapor deposition process on the other side of the films. The thicknesses of the films were 200 μm. The volume fraction of the MWCNTs was varied from 1% to 6%, while the PZT volume fraction was held constant at 30%. The strain coefficient and capacitance were measured as a function of the MWCNT volume fraction, and were subsequently used to determine the effective dielectric constant of the composite. Samples that incorporated graphene electrodes had higher effective dielectric constants than samples that incorporated graphene-PMMA electrodes and those with no top electrode. For example, the maximum values of effective dielectric constant for the composite films were ∼4353, ∼1945 and ∼61, for samples having graphene, graphene-PMMA and no electrode respectively. Similarly, composite films with graphene electrodes produced strain coefficients, e.g., d 33 and d 31 that were larger than their counterparts. Sample surface morphology and sample composition were observed using SEM and measured using Raman Spectroscopy respectively. Improved dielectric properties observed for samples with graphene coatings are due to graphene's high carrier mobility and ability to readily conform to the surface of the sample.

Research paper thumbnail of Powering MEMS portable devices—a review of non-regenerative and regenerative power supply systems with special emphasis on piezoelectric energy harvesting systems

Smart Materials and Structures, 2008

Research paper thumbnail of An analytical model for the effective dielectric constant of a 0-3-0 composite

An analytical expression for prediction of the effective dielectric constant of a three phase 0-3... more An analytical expression for prediction of the effective dielectric constant of a three phase 0-3-0 ferroelectric composite is presented. The analytical results are verified with the experimental results from Nan et al. (2002, “Three-Phase Magnetoelectric Composite of Piezoelectric Ceramics, Rare-Earth Iron Alloys, and Polymer,” Appl. Phys. Lett., 81(20), p. 3831). The analytical model is extended to include the shape of a third phase inclusion to examine the influence of the shape (of the inclusion) on the effective dielectric constant of the composite. The dielectric constant increases as much as seven times when the aspect ratio of the conducting inclusion particle is increased from 1 (sphere) to 10 (spheroid). A comparison of the analytical predictions with the experimental values, which indicate that the increase in aspect ratio of the inclusions has a significant effect on the overall dielectric constant of the composite.

Research paper thumbnail of Fabrication of dome-shaped PZT-epoxy actuator using modified solvent and spin coating technique

Journal of Electroceramics, 2013

Research paper thumbnail of An investigation into the influence of electrically conductive particle size on electromechanical coupling and effective dielectric strain coefficients in three phase composite piezoelectric polymers

Composites Part A: Applied Science and Manufacturing, 2012

Research paper thumbnail of Piezoelectric Energy Harvesting: A Green and Clean Alternative for Sustained Power Production

Bulletin of Science, Technology & Society, 2008

Research paper thumbnail of Influence of aluminium inclusions on dielectric properties of three-phase PZT–cement–aluminium composites

Advances in Cement Research, 2014

Research paper thumbnail of Piezoelectric and Dielectric Properties of PZT-Cement-Aluminum Nano-Composites