Self-Powered Viscosity and Pressure Sensing in Microfluidic Systems Based on the Piezoelectric Energy Harvesting of Flowing Droplets

Abstract

The rapid development of microscaled piezoelectric energy harvesters has provided a simple and highly efficient way for building self-powered sensor systems through harvesting the mechanical energy from the ambient environment. In this work, a self-powered microfluidic sensor that can harvest the mechanical energy of the fluid and simultaneously monitor their characteristics was fabricated by integrating the flexible piezoelectric poly(vinylidene fluoride) (PVDF) nanofibers with the well-designed microfluidic chips. Those devices could generate open-circuit high output voltage up to 1.8 V when a droplet of water is flowing past the suspended PVDF nanofibers and result in their periodical deformations. The impulsive output voltage signal allowed them to be utilized for droplets or bubbles counting in the microfluidic systems. Furthermore, the devices also exhibited self-powered sensing behavior due to the decreased voltage amplitude with increasing input pressure and liquid viscosity. The drop of output voltage could be attributed to the variation of flow condition and velocity of the droplets, leading to the reduced deformation of the piezoelectric PVDF layer and the decrease of the generated piezoelectric potential.

Solution Blow Spinning of Polyvinylidene Fluoride Based Fibers for Energy Harvesting Applications: A Review

“…The absolute permittivity of the material ε (F/m) is given by , where is permittivity of free space (8.854 × 10 −12 F/m), and is dielectric constant (or relative permittivity) of the material [6]. PEMs can be embedded into the final products of daily use, for example, gas sensors, pressure sensors, parking sensors, and piezoelectric motors and mobile phones [7][8][9]. Although most used PEMs are ceramic-based, however, due to their brittleness and high density, they are not ideal candidates for applications demanding flexibility such as flexible electronic screens [10,11].…”

“…PEMs can be embedded into the final products of daily use, for example, gas sensors, pressure sensors, parking sensors, and piezoelectric motors and mobile phones [ 7 , 8 , 9 ]. Although most used PEMs are ceramic-based, however, due to their brittleness and high density, they are not ideal candidates for applications demanding flexibility such as flexible electronic screens [ 10 , 11 ].…”

Solution Blow Spinning of High-Performance Submicron Polyvinylidene Fluoride Fibres: Computational Fluid Mechanics Modelling and Experimental Results

“…In 1969, polyvinylidene fluoride (PVDF) was first reported as thermoplastic polymer piezoelectric material (PEM) exhibiting the piezoelectric activity [1]. PVDF based PEMs are classified as stimuli responsive materials and have been employed as standalone or as matrices in composites and layered structures to fabricate stimuli responsive systems for applications such as drug delivery and tissue engineering [2][3][4]. One of the applications of PVDF based PEMs is intelligent clothing to sense user activities in sports and personalized health care [5][6][7].…”

Sensing and memorising liquids with polarity-interactive ferroelectric sound

“…The development of electronic interfaces for humans to quantitatively gain and store the information of things including hazardous gases, chemical and biological liquids and powders that are readily exposable to humans is of great importance for the emerging biomedical and health care applications based on Internet of Things technologies 1–8 . The direct sensing, monitoring and storing of the information of liquids 9–12 having different polarities are significant challenges, in particular, through means related to human senses such as vision and smell 13–19 . In general, it is extremely difficult for human senses to distinguish two liquids that are mostly colourless and transparent, except through identification based on their unique smell, which is rarely recommendable owing to the possible toxicity of volatile liquids.…”