Transcript Thermochromic Sensor

Green Product Design of
Temperature Sensors
Maria Nydia Ruiz Felix
[email protected]
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Thermochromism

The ability of a substance to change color due to a
change in temperature
T<Activation Point =72°F
After Activation T=155°F
M. A. White and M. LeBrlanc. “Thermochromism in Commercial Products”,
Journal of Chemical Education, 76, 1999.
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Temperature Label Mechanism of
Operation: Chemical/Physical System



Three component system
Solvent, acid, leuco dye
Operation



Solvent undergoes physical change from
solid to liquid
Allowing reaction between acid and dye
Color change results
M. A. White and M. LeBrlanc. “Thermochromism in Commercial
Products”, Journal of Chemical Education, 76, 1999.
3
Temperature Label Mechanism
of Operation: Physical



Based on melting point
Single component
Binary mixture
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Types of Sensors

Electronic



Cost approximately
$30
More Waste
disposal
Multiple uses

Thermochromic



Cost approximately
$0.30
Less waste disposal
One use
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Applications

Food industry and Pharmaceuticals


monitor shelf life and product quality
Textile and commercial product industries

developed to produce color change for a wide range
of specific predetermined temperatures
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Reverse Engineering:
Label Dissection
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Reverse Engineering:
Label Dissection
1.
2.
3.
4.
5.
6.
Clear plastic cover with the printed information 12.14 x 13.17 x 0.07 mm
Organic Crystals 0.003g
Adhesive
Black absorbent paper 5.17mm diameter x 0.21mm
Adhesive
Opaque (white) plastic 12.14 x 13.17 x 0.10 mm
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Principle of Operation

Steps:




Initial state – opaque crystals
At response state - melts
Final State – absorbed liquid
Black color observed
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Sensor Prototype Fabrication
1.
2.
3.
4.
5.
Transparent plastic
Organic crystals
Adhesive
Black colored filter paper
Double sided tape
double
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Transparent plastic

Polylactic Acid

3M™ Water Soluble Wave Solder Tape
5414 Transparent

3M™ Flame Retardant Sealing Tape 398FR
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Double sided tape

Polylactic Acid

3M™ Glass Cloth Tape 398FR White

420 Acrylic Adhesive
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Adhesive

Polyvinyl Ethers


DURO-TAK®80-1077
Water Base

NACOR®38-348A
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Mixture 1
Substance A




Molecular Weight – 152.15
g/mol
Melting Point – 125 oC
Safety Hazards
Mild eye irritant
No significant health risk
Substance B




Molecular Weight – 202.25
g/mol
Melting Point – 131 oC
Safety Hazards
Irritating to eyes and skin in
large quantities
No significant health risk
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Phase diagram
Eutectic
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Phase Diagram
Substance B
Substance A
Sensors
280
270
129
260
250
119
240
230
109
220
210
Temperature (°C)
Temperature (°F)
Melting point
99
0.0
0.2
0.4
0.6
0.8
1.0
Mole fraction of Substance 2
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Determination of activation time
and temperature

Procedure (Thermo box)
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

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
Heated box
Attached the temperature label
Restabilized the temperature
Increased temperature
Check the color change and time
Sensors tested


2 commercial sensors
Rowan sensors
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Activation Temperature

Data follows X=Y trend
Accuracy



Commercial sensors ±
0.4°C
Rowan sensors ± 0.83°C
Specification of the
commercial sensors
± 1°C
300
Temperature change (°F)

250
200
Commercial 1
Commercial 2
Rowan 153 S
Rowan 257 S
Rowan 185 W
Rowan 270 W
150
100
50
0
0
50
100
150
200
250
300
Temperature specified (°F)
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Activation Time
Commercial
sensors 3 s
 Rowan


Solvent base
adhesive 6 s
Water base
adhesive 4 s
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7
Commercial 1
6
Dtime (s)

9
Commercial 2
5
Rowan 153 S
4
Rowan 257 S
3
Rowan 185 W
2
Rowan 270 W
1
0
0
50
100
150
200
250
300
Temperature change(°F)
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Results

Produced prototype sensors in the temperature
ranges of

100 – 298°F

Ten Thermochromic substances

Future Work

Life Cycle Assessment
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Acknowledgements
Dr. Hesketh
 Dr. Newland
 Dr. Kuciauskas
 Marvin Harris

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