Abstract:
Strain sensors are devices used in applications such as electronic skin, prosthetic limbs,
e-textiles, and many more, for measuring the physical elongation of a desired structure
under a given or applied force. An artificial throat, using a strain sensor, was recently
developed as an aid for speech impaired individuals. Strain sensors have been
developed using graphene and Polyimide (PI) with a reported gauge factor ranging
from 5~120. In this work, a strain sensor was developed through laser scribing. Laser
scribing is a recent and facile technology used for printed electronics, whereby
complex geometries and patterns can be drawn very easily. The laser scribing method
relies on the property of certain materials to form a graphene-like conductive material
upon irradiation by lasers. Polyimide and graphene oxide (GO) are two such materials.
In these experiments, 2×3 cm sheets of polyimide were taken and a 1×1 cm box on the
sheet was printed using a laser patterning setup of 450 nm wavelength. Graphene oxide
solution was drop-casted on the reduced polyimide sheet of 1×1 cm, to increase its
sensitivity, and then the drop-casted graphene oxide is reduced using the same laser.
The strain sensor was characterized by a six-axis strain testing rig. In the preliminary
results, the normalized resistance was plotted against strain and the gauge factor (GF)
was calculated. The intensity of the laser was varied, and different gauge factors were
calculated. The effect of laser intensity was investigated. The gauge factor was found
to be in the range of 20-111 and was compared with the polyimide reduced strain
sensor (without drop-casting process).
