Preparation and characterization of potassium sodium niobate nanofibers by electrospinning

Abstract

In this work, we describe the electrospinning of (K,Na)NbO3 fibers and the effect of calcination temperature on the final phase composition. The envisaged application is for the fabrication of ferroelectric sensor hybrid materials. A solution of potassium acetate, sodium methoxide, and niobium ethoxide dissolved in methanol, acetylacetone, and acetic acid was mixed with polyvinylpyrrolidone (PVP) dissolved in methanol, producing a viscous solution for electrospinning. Confirmation that the proposed equation on the average diameter of fibers produced from high viscosity solutions was larger than that of a lower viscosity solution was made. A scanning electron microscopy (SEM) study showed the fibers to be cylindrical, smooth with diameters of around 400 nm and an aspect ratio >1000. The electrospun fibers were calcined from 700°C to 1050°C observing the fiber morphology. With increasing calcining temperature, the grain size increased. The calcined (K,Na)NbO3 nanofibers were brittle and generally found to display the “necklace effect.”

BaTiO3 nanotubes by co-axial electrospinning: Rheological and microstructural investigations

“…A further increase in the crystallite size (from 63 to 87 nm), and a further increase in c/a ratio to 1.0097 can be observed when increasing calcination temperature from 975 to 1000 °C. This increasing of grain size might be due to the beginning of the sintering stage at 950 °C [31]. Calcination at 1150 °C, caused the crystallite size of 95 nm, which is mainly due to the grain coarsening whilst the tetragonality is about 1.010.…”

“…The other method is the electrospinning, which is mainly a top-down approach. This method has been widely used to produce micro or nanofibers of both polymeric [27][28][29] and ceramic materials [30][31][32][33][34]. Electrospinning can also be modified and employed to fabricate different kinds of nanofibers with various structures and morphologies such as, porous [35,36], ribbon [37], helical [38], core/shell [39][40][41] and hollow [42][43][44].…”

“…There are several reports on synthesizing BT nanofibers by electrospinning technique for use in different applications [33,[45][46][47][48][49]. Previously, at Empa, electrospinning has been successfully utilized to produce BT [50] and other different ceramic nanofibers [31,32,[51][52][53][54]. However, there are not many reports on fabrication of BT NTs by electrospinning specially using co-axial technique.…”

Electrospun (K,Na)NbO3 Piezoceramic Fibers for Self‐Powered Tactile Sensing Application

“…[54][55][56] Lusiola et al explored in detail the aspects of the preparation of KNN fibers, and the influence of electrospinning process parameters and calcination conditions on the morphology of fibers. [57] To quantify the piezoelectric properties of electrospun KNN fiber mats, Yousry et al prepared randomly aligned and directionally aligned nanofiber webs, and estimated the (d 33(eff ) ) to be at 75 and 98 pm V À1 , respectively, using a laser scanning vibrometer. [54] To enhance the piezoelectric properties of pristine KNN fibers, Ichangi et al doped the fibers with Li þ and Ta 5þ ions at the A-and B-site in the perovskite lattice.…”

Structure and High Performance of Lead-Free (K0.5Na0.5)NbO3 Piezoelectric Nanofibers with Surface-Induced Crystallization at Lowered Temperature

“…In a follow-up work, they observed strong anisotropy in the piezoelectric strain coefficient d 33 with piezoelectric force microscopy (PFM), being 18.3 pm V –1 for the on-axis fiber and 75.8 pm V –1 for the out-of-axis fiber . Several additional reports attempted to reproduce the synthesis of high-quality KNN nanofibers. − In these handful studies on KNN nanofibers, the crystallization mechanism and the macroscopic piezoelectric properties remain unexploited. Hence, the present study intends to investigate the crystallization process of KNN nanofibers prepared by electrospinning from a solution with an excess of alkali ions and stabilizing agent and to evaluate the dielectric, ferroelectric, and piezoelectric properties over a macroscale on the nanofiber web.…”