The Piezoelectric, The Piezoelectric, Electric, and Electric, and
Dielectric Dielectric Properties of Properties of Amorphous Amorphous
Polyimide PolymersPolyimide PolymersA research investigation by A research investigation by Paul Paris and Dr. Joseph Paul Paris and Dr. Joseph
Ficht under the direct Ficht under the direct supervision of Dr. Zoubeida supervision of Dr. Zoubeida
OunaiesOunaies
Project One SynopsisProject One Synopsis
To investigate the effect of To investigate the effect of carbon nanotubes (CNT’s) in carbon nanotubes (CNT’s) in terms of content and method terms of content and method of processing, on the of processing, on the piezoelectric, electric, and piezoelectric, electric, and dielectric properties of an dielectric properties of an amorphous piezoelectric amorphous piezoelectric polyimide polymer.polyimide polymer.
Project Two SynopsisProject Two Synopsis
To investigate the effect of To investigate the effect of carbon nanofibers (CNF’s) carbon nanofibers (CNF’s) and carbon nanotubes and carbon nanotubes (CNT’s) on the mechanical, (CNT’s) on the mechanical, electrical, and dielectric electrical, and dielectric properties of PVDFproperties of PVDF
What is an Amorphous What is an Amorphous Polymer?Polymer?
A polymer with randomly oriented A polymer with randomly oriented molecules that are intertwined like molecules that are intertwined like cooked spaghetticooked spaghetti
The polymer has a glasslike, The polymer has a glasslike, transparent appearancetransparent appearance
ExamplesExamples:: Polystyrene-hard and rigid plastic at Polystyrene-hard and rigid plastic at
room temperatureroom temperature Polyethyl Acrylate- soft, flexible rubbery Polyethyl Acrylate- soft, flexible rubbery
material at room temperaturematerial at room temperature
ElectroactivityElectroactivity
E
l’<l
What Is What Is Piezoelectricity?Piezoelectricity?Actuator function:Actuator function:
Sensor function:Sensor function:
Force
PiezoelectriciPiezoelectricityty
• Requires dipole orientation• Dipoles collectively respond to field due to remnant polarization• Sensing and actuation capability
What is a Polyimide ?What is a Polyimide ?
A polymer of imide monmers that in A polymer of imide monmers that in conjunction with the carbon conjunction with the carbon nanotubes, produce a composite that nanotubes, produce a composite that has excellent physical, electrical, and has excellent physical, electrical, and mechanical propertiesmechanical properties
Light weight and flexible Multilayer insulators Resistance to harsh space environment Good support structures
Structure of bCN(APB/ODPA), Polyimide
What is Polyvinyl What is Polyvinyl Difluoride?Difluoride?
Polyvinyl Difluoride (PVDF) is a Polyvinyl Difluoride (PVDF) is a polymer comprised of hydrogen, polymer comprised of hydrogen, carbon, and fluorine atoms. It is a carbon, and fluorine atoms. It is a polar substance as the hydrogen polar substance as the hydrogen atoms lose electrons to the fluorine atoms lose electrons to the fluorine atoms. In 1969 it was first observed atoms. In 1969 it was first observed that this polar or dipole nature could that this polar or dipole nature could be used to generate piezoelectricty.be used to generate piezoelectricty.
What is a Carbon What is a Carbon Nanotube?Nanotube?
A thin layer of A thin layer of graphene rolled into a graphene rolled into a seamless tube and seamless tube and capped at both endscapped at both ends
Electrical, Thermal, Electrical, Thermal, and Mechanical and Mechanical properties of graphite properties of graphite help to improve help to improve electrical conductivity, electrical conductivity, thus enhancing the thus enhancing the structural composition structural composition of the polymerof the polymer
Single Walled Carbon Nanotube (SWNT)
What are some What are some applications?applications?
Smart Ski (ACX)
NASA Applications•Electro-optical Device Technologies• Precise positioning• Switches
Multifunctional Membranes•Antennas• Reflectors • Smart skins• Tuning and positioning inflatable structures
Biomedical•Portable Artificial organs•lightweight fetal heart monitor•Ultrasonic imaging•Tissue engineering
Health monitoring
Flow sensors and actuators
Inflatable Antennae
Ultrasonic imaging
Experimental DetailsExperimental Details SEM images to SEM images to
investigate dispersion of investigate dispersion of CNT’sCNT’s
Electrode samples for Electrode samples for electrical and dielectric electrical and dielectric measurementsmeasurements
Measurement Measurement comparison using comparison using thermally stimulated thermally stimulated current measurements current measurements (TSC)(TSC) Dielectric and Dielectric and
electrical properties electrical properties as a function of as a function of frequency at room frequency at room temperature before temperature before and after polingand after poling
Pole at a single Pole at a single voltage; time; voltage; time; temperaturetemperature
SEM Results of BCN SEM Results of BCN SWNTSWNT
.05wt% BCN SWNT Samples
SEM Results of PVDF+ SEM Results of PVDF+ DWNTDWNT
Results of Dielectric Results of Dielectric Constant Testing on Constant Testing on
PolyimidePolyimideBeta-CN Samples
0
10
20
30
40
50
1.00E+00 1.00E+01 1.00E+02 1.00E+03 1.00E+04 1.00E+05 1.00E+06
Frequency (Hz)
Die
lec
tric
Co
ns
tan
t
Pure CN
.05wt% HIPCO
.05wt% Laser
Results of Dielectric Results of Dielectric Testing on PVDFTesting on PVDF
0
20
40
60
80
100
120
140
160
180
200
100 1000 10000 100000 1000000 10000000
Frequency [Hz]
Die
lec
tric
co
ns
tan
t
0.25% CNF
0.25% DWNT
PVDF
Results of Dielectric Results of Dielectric Testing on PVDF Testing on PVDF
(Continued)(Continued)
1.E-08
1.E-07
1.E-06
1.E-05
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07
Frequency [Hz]
Co
nd
uc
tiv
ity
[S
/m]
0.25% CNF
0.25% DWNT
PVDF
Results of Adding CNF and Results of Adding CNF and DWNT to PVDFDWNT to PVDF
Pure PVDF is an insulator but adding carbon Pure PVDF is an insulator but adding carbon nanofibers increased the dielectric constant nanofibers increased the dielectric constant and conductivity. Adding the double walled and conductivity. Adding the double walled nanotubes, however, greatly increased the nanotubes, however, greatly increased the dielectric constant and conductivity and now dielectric constant and conductivity and now shows the characteristics of a conductor.shows the characteristics of a conductor.
QUESTIONS?QUESTIONS?
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