Pressure sensors can transform physical pressure signal to electrical signal, so they
have great potential for the applications in automatic control, medical diagnosis, smart
robots and touch screens. Among the pressure sensors, the flexible pressure sensors
using the PDMS film as substrate can be applied to curved surfaces and tolerate
buckling, so can work effectively in the harsh situation.
This thesis presents a resistance-type flexible pressure sensor with an air gap
structure. To make the CNT/PDMS flexible conductive film, we disperse the CNT
powder in SDS solution and synthesize the CNT film on the MCE filter membrane by
the vacuum filtration method. In order to separate the CNT film from the filter
membrane, the researcher immerse the filter membrane loaded with the CNT film in
acetone solution to dissolve the filter membrane. And this thesis use the ground glass
chips and smooth glass chips as templates to make smooth PDMS film and
micro-patterned PDMS film. Finally, the CNT film can be transferred onto the PDMS
films formed the flexible conductive film. In this thesis, we use the scanning electron
microscope, Raman spectrometer, diamonds resistance instrument to analyze the
properties of the CNT/PDMS film. According to the test results, the CNT/PDMS film
using the smooth PDMS film as substrate is uniform, stable and has perfect
To analyze the influence of the air gap structure on the pressure sensor and
compare the performance of the pressure sensors with different structures, this thesis
has assembled four kinds pressure sensors (the traditional pressure sensor, the pressure
sensor with air gap structure with one layer PDMS strips, the patterned pressure sensor,
the pressure sensor with air gap structure with two layer PDMS strips). Then the thesis
test performance index of responsivity, stability, sensitivity and the low detectable
pressure limit of four kinds pressure sensors. Among different kinds of pressure sensors,
the pressure sensor with one layer PDMS strips has the highest sensitivity (58.9 kPa
-1
in
the range of 1-5 Pa, 0.66 KPa
-1
in the range of 5-100 Pa) and the smallest low detectable
pressure limit(1 Pa). So the air gap structure can improve the pressure sensors’
To analyze the mechanism of the pressure sensor, the thesis has built up the