posted on 2021-03-19, 12:41authored byQiushun Zou, Kai He, Jian Ou-Yang, Yueli Zhang, Yang Shen, Chongjun Jin
High-performance
strain sensors, composed of various artificial
sensing materials on/in stretchable substrates, show great promise
for applications in flexible electronic devices. Here, we demonstrated
a highly sensitive and durable strain sensor consisting of a ribbon
of close-packed sea-urchin-shaped silver nanoparticles (SUSNs) sandwiched
between two layers of poly(dimethylsiloxane) (PDMS). Each of SUSNs
possesses high-density and spherically distributed sharp spines over
the body, which promotes electron transduction and further improves
signal detection. This SUSN-based sensor possesses a desirable integration
of high sensitivity (a gauge factor of 60) and large stretchability
(up to 25%) at tensile sensing, broadening its application in wearable
devices. Moreover, it also shows fast response (48 ms), good reproducibility,
and long-term stability (>2500 cycles at 20% strain). It can also
be used to detect compressing (sensitivity up to 31.5) and folding-type
bending deformations. The sensing mechanism, the resistance of the
sensors varying as the deformation load, results from the inter-spine
contacts change and the microcracks evolution caused by variation
in the gap between SUSNs. The sensor’s sensitivity at different
degrees of strain was also achieved by controlling the width of the
close-packed SUSNs ribbon. For practical demonstration, the SUSN-based
sensors could be used as wearable devices for monitoring human activities
ranging from subtle deformations to substantial movements.