Development and fabrication of carbon nanotube (CNT) based pH sensor

The development, fabrication and characterization of single-walled carbon nanotubes (SWCNTs) based pH sensor using aligned SWCNT were reported. The SWCNT alignment is defined by a single carbon nanotube aligned between the fabricated electrodes. This research involves the study of SWCNTs dispersion,...

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Main Author:	Low, Foo Wah
Format:	Thesis
Language:	English
Subjects:	Nanotubes > Carbon content. Nanotechnology Carbon nanotube (CNT) pH sensor Carbon nanotubes based sensor Biosensors
Online Access:	http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/31218/1/Page%201-24.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/31218/2/Full%20text.pdf
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spelling	my-unimap-312182014-01-15T03:39:19Z Development and fabrication of carbon nanotube (CNT) based pH sensor Low, Foo Wah The development, fabrication and characterization of single-walled carbon nanotubes (SWCNTs) based pH sensor using aligned SWCNT were reported. The SWCNT alignment is defined by a single carbon nanotube aligned between the fabricated electrodes. This research involves the study of SWCNTs dispersion, alignment of SWCNT between microgap electrodes and characterization on the effect of change in the pH level on the impedance, conductance and capacitance of the aligned SWCNT. In the SWCNT dispersion study, the SWCNTs were dispersed in Isopropyl Alcohol (IPA), Dichloromethane (DCM), Acetone and Triton-X 100. It was found that SWCNT disperse best in the IPA solution because the dispersed SWCNTs have remained dispersed which can be observed from the clear solution even after 14 days as compared to DCM, acetone and Triton-X 100. On the other hand, the SWCNTs in DCM, acetone and Triton-X 100 have shown a thick mass of coagulated SWCNT after 14 days of dispersion. A chrome mask which consists of 6 groups with different gap measurement was designed. Each group has 5 different designs to facilitate the SWCNT alignment. After that, the devices were fabricated using gold material as electrode to increase the electrical conductivity and permittivity of the device. The SWCNT was then aligned on the fabricated devices using AC dielectrophoresis method. The AC dielectrophoresis method involved control in the voltage and frequency to increase the chance of SWCNT alignment between the microgap. The devices were brought to electrical characterization before and after SWCNT alignment to compare the effect on the device capacitance. It was found that the capacitance before SWCNT alignment is higher than after SWCNT alignment of the device. Before SWCNT alignment, the dielectric of the capacitive device is air which is a better insulator than SWCNT that is a semiconductor material. This phenomenon is due to the fact that dielectric decrease electric field and capacitance is inversely proportional to electric field. On the other hand, the device was tested for its impedance using pH buffer solutions. As pH value was decreased, impedance has also decreased. The hydrogen ions were found to bind to the carboxyl group of the SWCNT creating positive holes in the SWCNT hence increasing its conductivity. As a conclusion, this research successfully demonstrated the process to design, fabricate and characterize the SWCNT based sensor. Universiti Malaysia Perlis (UniMAP) 2013 Thesis en http://dspace.unimap.edu.my:80/dspace/handle/123456789/31218 http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/31218/1/Page%201-24.pdf be9b4639abcc92ea3fc46a953566eebd http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/31218/2/Full%20text.pdf f5cb57a9ee1beaf4ab452744f4f61b11 http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/31218/3/license.txt 8a4605be74aa9ea9d79846c1fba20a33 Nanotubes --Carbon content. Nanotechnology Carbon nanotube (CNT) pH sensor Carbon nanotubes based sensor Biosensors Institute of Nanoelectronic Engineering
institution	Universiti Malaysia Perlis
collection	UniMAP Institutional Repository
language	English
topic	Nanotubes --Carbon content. Nanotechnology Carbon nanotube (CNT) pH sensor Carbon nanotubes based sensor Biosensors
spellingShingle	Nanotubes --Carbon content. Nanotechnology Carbon nanotube (CNT) pH sensor Carbon nanotubes based sensor Biosensors Low, Foo Wah Development and fabrication of carbon nanotube (CNT) based pH sensor
description	The development, fabrication and characterization of single-walled carbon nanotubes (SWCNTs) based pH sensor using aligned SWCNT were reported. The SWCNT alignment is defined by a single carbon nanotube aligned between the fabricated electrodes. This research involves the study of SWCNTs dispersion, alignment of SWCNT between microgap electrodes and characterization on the effect of change in the pH level on the impedance, conductance and capacitance of the aligned SWCNT. In the SWCNT dispersion study, the SWCNTs were dispersed in Isopropyl Alcohol (IPA), Dichloromethane (DCM), Acetone and Triton-X 100. It was found that SWCNT disperse best in the IPA solution because the dispersed SWCNTs have remained dispersed which can be observed from the clear solution even after 14 days as compared to DCM, acetone and Triton-X 100. On the other hand, the SWCNTs in DCM, acetone and Triton-X 100 have shown a thick mass of coagulated SWCNT after 14 days of dispersion. A chrome mask which consists of 6 groups with different gap measurement was designed. Each group has 5 different designs to facilitate the SWCNT alignment. After that, the devices were fabricated using gold material as electrode to increase the electrical conductivity and permittivity of the device. The SWCNT was then aligned on the fabricated devices using AC dielectrophoresis method. The AC dielectrophoresis method involved control in the voltage and frequency to increase the chance of SWCNT alignment between the microgap. The devices were brought to electrical characterization before and after SWCNT alignment to compare the effect on the device capacitance. It was found that the capacitance before SWCNT alignment is higher than after SWCNT alignment of the device. Before SWCNT alignment, the dielectric of the capacitive device is air which is a better insulator than SWCNT that is a semiconductor material. This phenomenon is due to the fact that dielectric decrease electric field and capacitance is inversely proportional to electric field. On the other hand, the device was tested for its impedance using pH buffer solutions. As pH value was decreased, impedance has also decreased. The hydrogen ions were found to bind to the carboxyl group of the SWCNT creating positive holes in the SWCNT hence increasing its conductivity. As a conclusion, this research successfully demonstrated the process to design, fabricate and characterize the SWCNT based sensor.
format	Thesis
author	Low, Foo Wah
author_facet	Low, Foo Wah
author_sort	Low, Foo Wah
title	Development and fabrication of carbon nanotube (CNT) based pH sensor
title_short	Development and fabrication of carbon nanotube (CNT) based pH sensor
title_full	Development and fabrication of carbon nanotube (CNT) based pH sensor
title_fullStr	Development and fabrication of carbon nanotube (CNT) based pH sensor
title_full_unstemmed	Development and fabrication of carbon nanotube (CNT) based pH sensor
title_sort	development and fabrication of carbon nanotube (cnt) based ph sensor
granting_institution	Universiti Malaysia Perlis (UniMAP)
granting_department	Institute of Nanoelectronic Engineering
url	http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/31218/1/Page%201-24.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/31218/2/Full%20text.pdf
_version_	1747836785237426176

Development and fabrication of carbon nanotube (CNT) based pH sensor

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