Highly Sensitive and Multifunctional Tactile Sensor Using Free-standing ZnO/PVDF Thin Film with Graphene Electrodes for Pressure and Temperature Monitoring

Abstract

We demonstrate an 80-μm-thick film (which is around 15% of the thickness of the human epidermis), which is a highly sensitive hybrid functional gauge sensor, and was fabricated from poly(vinylidene fluoride) (PVDF) and ZnO nanostructures with graphene electrodes. Using this film, we were able to simultaneously measure pressure and temperature in real time. The pressure was monitored from the change in the electrical resistance via the piezoresistance of the material, and the temperature was inferred based on the recovery time of the signal. Our thin film system enabled us to detect changes in pressure as small as 10 Pa which is pressure detection limit was 103-fold lower than the minimum level required for artificial skin, and to detect temperatures in the range 20–120°C.

Hybrid lead-free polymer-based nanocomposites with improved piezoelectric response for biomedical energy-harvesting applications: A review

“…A hybrid free-standing ZnO/PVDF film was demonstrated to be a highly sensitive sensor for independent temperature and pressure monitoring [200]. A nanocomposite film with a thickness of 80 µm, which is only 15% of the thickness of the human epidermis, was loaded with vertically grown ZnO NRs 300 nm in length and 85 nm in diameter ( Figure S4a In another study [201], PVDF and tetrapod ZnO nanostructures were hybridised on a flexible fabric substrate with an area of 20×7 cm 2 ( Figure S6a).…”

“…rGO and Gr nanosheets seem to be promising nanofillers for obtaining strong sensing capabilities with low detection limits [31,203,206], especially in combination with specific film geometries and a multilayered sensor structure [203]. Good sensitivity was also obtained for microstructured piezopolymers loaded with metal oxides [200].…”

Wearable high-performance pressure sensors based on three-dimensional electrospun conductive nanofibers

“…Three-dimensional (3D) structured conductive polymeric materials are promising for achieving highly flexible pressure sensors. In the last few years, various structures and materials have been developed to fabricate ultrasensitive pressure sensors that can effectively collect pressure stimuli in the low-pressure regime (<10 kPa) [11][12][13][14][15][16] . However, several obstacles limit the practical application of such sensors.…”

Physical sensors for skin‐inspired electronics

“…Based on the pyroelectric effect of PVDF, Xue et al prepared a self‐powered temperature sensor for respiratory monitoring (Figure B) . In addition, researchers used the enhanced electrophysical coupling effects of nanocomposites to improve the stability and achieved multiple functions . For example, Chen et al fabricated a pyroelectric temperature sensor with micropatterned (1 − x )Pb(Mg,Nb)O 3 ‐ x PbTiO 3 (PMN‐PT) ribbons, which showed excellent piezoelectric and pyroelectric properties (Figure C) .…”