A Mini Review on Electrospun PVDF- Doped Metal Oxide Nanoparticles for Sensor Applications

Abstract

Due to the over consumption of natural sources like petroleum and coal, researchers have started paying attention to balance the energy crisis in alternative way such as fabricating energy storage and harvesting devices. Identifying polymers having appreciable dielectric and piezoelectric properties for fabricating energy storage devices is an area of interest to our research group. Among the many fluoropolymers, polyvinylidene fluoride (PVDF) is well-known since 1960s and is preferred for its exhibition of inordinate mechanical properties and complicated polymorphism. Usually, PVDF exhibits four crystalline forms namely α, β, γ and δ. Most common polymorph was α-crystalline phase and upon crystallization from melt, β-phase could be formed. β-phase is the most important polymorph with excellent piezoelectric and pyroelectric properties [1]. The effect of nanoparticles (NPs) in improving the electrical characteristics of PVDF has generated numerous publications since the last decade and a review paper in this topic will be of interest to many researchers working in this field. Basically, NPs can be classified as atom clusters with at least 1-D in the nanoscale size range (1~100 nm). NPs are used in diverse applications owing to their unique physical and electrical (optical, magnetic & catalytic) properties. In recent times, many research groups have focussed on synthesizing Fe, Co and Ni oxides based magnetic NPs for data storage and sensor applications due to their higher thermal and mechanical stability which is essential to survive in severe working conditions [2]..More importantly, transition metal cations can exist in several different valence states [3], and their crystallite size increased with increasing addition of metal doping [4].  Incorporation of metal oxides and doped metal oxides with PVDF plays a vital role in the improvement in piezoelectric sensor sensitivity. This mini-review presents recent advancement in metal oxides doping with PVDF and its effectiveness towards the sensors application. This mini-review focuses to provide the key note for synthesising a novel and economically cheap material for energy storage and harvesting process. From the overall literature, it was observed that most of the published reviews and research articles explained only on synthesis of metal oxides and doped metal oxide in different synthetic methods. In our review, we aim to bring about the correlation of metal oxide and doped metal oxide with PVDF and the resultant changes in electrical properties. From the literature review, it was clear that doping a metal with other metal oxides enhancing the crystallite size, and it will enhance the sensitivity of material for sensor applications. The core objectives of the review are (i). How the metal oxides and doped metal oxides with PVDF will be prepared by simple chemical synthesis? and (2). How it will be useful to fabricate the energy storage and energy harvesting devices which is going to fulfil the future energy imbalance? Acknowledgement: This work was supported by CSIR, Government of India under CSIR-EMR-II scheme (03(1450)18/EMR-II dt.05-06-2018). A.A.P also thank VIT for providing ‘VIT SEED GRANT’ for carrying out this research work.