Cellulose paper-based sensors have several advantages: 1) They are flexible, bendable, and foldable since they are fabricated on paper. 2) They are biodegradable and more environmentally friendly than solid-state sensors. 3) They can be manufactured using low-cost roll-to-roll printing or inkjet printing processes. Potential applications include biomedical sensors, structural health monitoring, intelligent packaging, and advertising. Carbon nanotubes deposited on paper can act as humidity, chemical, strain, or other types of sensors.

1. Cellulose paper based sensors
Jin-Woo Han & M. Meyyappan
Oct. 16 2012
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2. Advantages of paper based sensors
nsors fabricated on a paper
gas sensor, chemical detector, bio sensor, and strain gauge
tures
Flexible, bendable, foldable
Bio-degradable: green technology
Robust in cryo-temperatures
role-to-role printing or ink-jet printing process
Extremely cheaper than solid-state sensors: disposable
SA Applications
Biomedical sensor, single-time use sensor
etection of structural defects and cracks, structural health
monitoring
Commercial:Intelligent packaging, advertising banner, newspaper
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3. Example: humidity/water vapor sensing
2 1.8 1.8
RH=
RH=10% RH=10% 10%
1.6 1.6
Conductance (µ S)
Conductance (µ S)
1
Current (µ A)
CNT on paper 1.4 30%
1.4
0
50% 40%
50% Bare paper 1.2
1.2
-1
1.0 60%
1.0
-2 60%
0.8
-1 0 1 0 50 100 150 200 250 -40 0 40 80 120 160 200
Voltage (V) Time (sec) Time (min)
The chemical reaction between H 2O and CNT surface changes
the conductivity of CNT according to the relative humidity.
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4. Example: displacement(strain) gauge
CNT
Paper
Flat state Tensile stress Compressive stress
-less conductive -more conductive
1.2
Early stage 120
Steady stage
1.0
Conductance (nS)
Conductance (µ S)
100
0.8
80
0.6 60
0.4 40
0.2 20
0 2 4 6 8 10 100 105 110
Frequency (#) Frequency (#)
After stabilization, the connectivity with neighboring CNTs
changes the conductivity of CNT according to the bending
curvature.
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