(649c) Kirigami-Enabled, Passive Resonant Sensors for Wireless Deformation Monitoring

A passive resonant sensor with kirigami
patterning is presented to wirelessly report material deformation in closed
systems. The sensors were fabricated from copper-coated polyimide by etching a
conductive Archimedean spiral and then laser cutting kirigami
patterns. The sensor response was defined as the resonant frequency in the
transmission scattering parameter signal (S₂₁), which was captured
via a benchtop vector network analyzer. The sensors were tested over a 0-22 cm
range of extension and showed a significant shift in resonant frequency (e.g.
90 MHz shift for 10 cm stretch). Furthermore, the effect of resonator coil
pitch on the extension sensor gain (MHz/cm) and linear span of the sensor was
studied.  The repeatability of the sensor
gain was confirmed by performing hysteresis cycles. The sensors were coated
with polydimethylsiloxane films to protect from electrical shorting in aqueous
environments.  The coated resonators were
placed in a PVC pipe to report flow rates. The sensor with 1 mm coating was
found to have the largest gain (0.17 MHz mso-ascii-font-family:Calibri;mso-ascii-theme-font:minor-latin;mso-hansi-font-family:
Calibri;mso-hansi-theme-font:minor-latin;mso-char-type:symbol;mso-symbol-font-family:
Symbol">×s/mL)
and linear span (10-100 ml/s). Thus, flexible resonant sensors with kirigami-inspired patterns can be tuned via geometric and
coating considerations to wirelessly report a large range of extension lengths
for potential uses in health monitoring, motion tracking, deformation
detection, and soft robotics.

normal">Charkhabi S, Chan
YJ, Hwang D-G, Frey ST, Bartlett MD, Reuel NF Kirigami-Enabled,
Passive Resonant Sensors for Wireless Deformation Monitoring. Advanced
Materials Technologies, 0(0):1800683. https://doi.org/10.1002/admt.201800683