Piezoelectric nanogenerator for bio-mechanical strain measurement

Abstract

Piezoelectric materials have attracted more attention than other materials in the field of textiles. Piezoelectric materials offer advantages as transducers, sensors, and energy-harvesting devices. Commonly, ceramics and quartz are used in such applications. However, polymeric piezoelectric materials have the advantage that they can be converted into any shape and size. In smart textiles, polyvinylidene fluoride (PVDF) and other piezoelectric polymers are used in the form of fibers, filaments, and composites. In this research, PVDF nanofibers were developed and integrated onto a knitted fabric to fabricate a piezoelectric device for human body angle monitoring. Scanning electron microscopy and X-ray diffraction analyses were used to study the morphology and to confirm the beta phase in fibers. The results reveal that the nanofibers made from solutions with high concentration were smooth and defect-free, compared to the fibers obtained from solutions with low concentration, and possess high crystallinity as well. Under high dynamic strain more output voltage is generated than under low dynamic strain. The maximum current density shown by the device is 172.5 nA/cm2. The developed piezoelectric nanofiber sensor was then integrated into a knitted fabric through stitching to be used for angle measurement. With increasing bending angle, the output voltage increased. The promising results show that the textile-based piezoelectric sensor developed in this study has a great potential to be used as an angle measuring wearable device for the human body due to its high current density output and flexibility.

FABRICATION SENSORS BASED ON NANOCOMPOSITES ZnO/PVDF

“…Electric field and stretching force as of electrospinning practice align dipoles in the nanofiber crystal such as the nonpolar αphase their benefit is converted into polar β-phase. Therefore electrospinning techniqueswithin-poling and situ mechanical stretchings can create piezoelectric PVDF nanofibers [8][9][10].…”

Recent Developments in Textile Materials Based on the Piezoelectricity Concept

“…A study by Naeem et al [1] evinced the development of a piezoelectric textile device built from polyvinylidene fluoride (PVDF) nanofibers obtained from the electrospinning method incorporated into a knitted fabric with the aid of a sewing technique for use in monitoring the angles of the human body during a given activity. The results confirmed the piezoelectric behavior of the device, given that its electrical response increased as an increase in the curvature (angle variation) of the human body occurred [1].…”

“…Textile materials stand out more and more due to their technological characteristics, and one may evince the piezoelectric technology inserted in the area of textile materials [1].…”

“One-Step” Preparation Process for the Flexible and Breathable Piezoelectric Sensor

“…On the other hand, it is difficult to combine porosity and waterproofness. 27 Additive manufacturing shows great potential in overcoming the above-mentioned problems. Harada et al demonstrate a fully printed fingerprintlike three-axis tactile force and temperature sensor for artificial skin applications.…”

“…On the one hand, due to the relatively deficient structural design and material selection, , most of the reported sensors were multistep and assembled by tapes. On the other hand, it is difficult to combine porosity and waterproofness . Additive manufacturing shows great potential in overcoming the above-mentioned problems.…”