vii
TABLE OF CONTENTS
CHAPTER
1
TITLE
PAGE
DECLARATION
ii
DEDICATION
iii
ACKNOWLEDGEMENT
iv
ABSTRACT
v
ABSTRAK
vi
TABLE OF CONTENTS
vii
LIST OF TABLES
x
LIST OF FIGURES
xi
LIST OF ABBREVIATIONS
xiii
LIST OF SYMBOLS
xiv
INTRODUCTION
1
1.1 Background of study
1
1.2 Motivation of study
4
1.3 Objectives
4
1.4 Scope of project
4
1.5 Summary
5
viii
2
LITERATURE REVIEW
6
2.1
Introduction
6
2.2
Previous research on chemically gas sensor
6
2.2.1
An ideal gas sensor
7
2.2.2
Chemoresistive sensor arrays
8
2.2.3
Sensing material composites
11
2.3
3
4
5
Summary
13
METHODOLOGY
14
3.1
Introduction
14
3.2
Sensor design and fabrication process
15
3.3
Preparation of Chemoresistive sensor
17
3.3.1
Material introduction
18
3.3.2
Material preparation
20
3.3.3
Material coating techniques and results
21
3.3.4
Gas sensor chamber
24
3.4
Development of Interface circuit
25
3.5
Experimentation setup
27
3.6
Summary
31
RESULTS AND DISCUSSIONS
32
4.1
Introduction
32
4.3
Data preprocessing
32
4.4
PCA analysis
36
4.5
Summary
37
CONCLUSIONS AND FUTURE WORK
38
5.1
Introduction
38
5.2
Conclusions
38
5.3
Future work
40
ix
REFERENCES
41
Appendix A
44
x
LIST OF TABLES
TABLE NO.
TITLE
PAGE
3.1
Initial size of individual sensor array
16
3.2
The procedure of material deposition process.
18
3.3
Material specification
20
3.4
Material weight measurement based wt%
21
3.5
Initial resistance value of individual sensor
24
3.6
List of equipments and materials
29
xi
LIST OF FIGURES
FIGURE NO.
TITLE
PAGE
1.1
Electronic nose and human nose
3
2.1
A basic response of chemoresistive sensor
7
2.2
Partly coated chemoresistive sensor a) 300
8
Microsensor arrays b) Single microsensor array
fabrication diagram
2.3
Electrode configuration design a) 42 unique size of
9
each element b) Single geometry sensor fabrication
diagram
2.4
Fabrication diagram of FGS-PS composite thin film
10
field effect devices
2.5
Carbon black poymer composite after evaporation
13
process a) Initial state before odour exposure b) Upon
odour exposure
3.1
Methodology of the project
15
3.2
PCB design of sensor array
16
3.3
Sensor array fabrication diagram a) Before etching
17
process b) Complete fabrication process
3.4
Fabricated sensor arrays
17
xii
3.5
Four individual materials a) PVPD b) PEG c) Carbon
19
black d) Graphene
3.6
Mask coating
22
3.7
Material deposition technique
22
3.8
A chemoresistive sensor
23
3.9
Gas sensor chamber
25
3.10
Interface circuit diagram a) Circuit block diagram b)
26
Schematic draw of the circuit c) Circuit board
3.11
LABVIEW signal expressed 2009 program a) Signal
28
generation block diagram b) Front panel
3.12
Experimentation setup diagram
30
4.1
Normalized result a) Apple, b) Lemon, and c) Rose
34
4.2
PCA analysis of the measurement
36
xiii
LIST OF ABBREVIATIONS
E-nose
-
Electronic nose
FGS
-
Functionalized Graphene Sheet
PS
-
Polystyrene
PVPD
-
Poly-vinyl-pyrrolidone
PEG
-
Poly- ethyl-gycol
PCB
-
Printed Circuit Board
DAQ
-
Data Acquisiton
USB
-
Universal Serial Bus
PCA
-
Principal Component Analysis
cm
-
Centimeter
mm
-
Millimeter
µm
-
Micrometer
nm
-
nanometer
ml
-
Milliliter
xiv
LIST OF SYMBOLS
%
-
Percentage
Wt%
-
Percentage of Weight
Vol%
-
Percentage of Volume
-
Seconds
k
-
Kilo
R
-
Resistor
L
-
Length
A
-
Area
-
Resistivity
V
-
Volt
M
-
Mega
Ω
-
Ohm
T
-
Temperature
˚C
-
Degree of Celcius
θ
-
Angle
N2
-
Natrium dioxide
Au
-
Aurum
Cu
-
Copper
Cr
-
Chromium