Flexible piezocapacitive
sensors utilizing nanomaterial–polymer
composite-based nanofibrous membranes offer an attractive alternative
to more traditional piezoelectric and piezoresistive wearable sensors
owing to their ultralow powered nature, fast response, low hysteresis,
and insensitivity to temperature change. In this work, we propose
a facile method of fabricating electrospun graphene-dispersed PVAc
nanofibrous membrane-based piezocapacitive sensors for applications
in IoT-enabled wearables and human physiological function monitoring.
A series of electrical and material characterization experiments were
conducted on both the pristine and graphene-dispersed PVAc nanofibers
to understand the effect of graphene addition on nanofiber morphology,
dielectric response, and pressure sensing performance. Dynamic uniaxial
pressure sensing performance evaluation tests were conducted on the
pristine and graphene-loaded PVAc nanofibrous membrane-based sensors
for understanding the effect of two-dimensional (2D) nanofiller addition
on pressure sensing performance. A marked increase in the dielectric
constant and pressure sensing performance was observed for graphene-loaded
spin coated membrane and nanofiber webs respectively, and subsequently
the micro dipole formation model was invoked to explain the nanofiller-induced
dielectric constant enhancement. The robustness and reliability of
the sensor have been underscored by conducting accelerated lifetime
assessment experiments entailing at least 3000 cycles of periodic
tactile force loading. A series of tests involving human physiological
parameter monitoring were conducted to underscore the applicability
of the proposed sensor for IoT-enabled personalized health care, soft
robotics, and next-generation prosthetic devices. Finally, the easy
degradability of the sensing elements is demonstrated to emphasize
their suitability for transient electronics applications.