Orientation of Electrospun Magnetic Nanofibers Near Conductive Areas

Abstract

Electrospinning can be used to create nanofibers from diverse polymers in which also other materials can be embedded. Inclusion of magnetic nanoparticles, for example, results in preparation of magnetic nanofibers which are usually isotropically distributed on the substrate. One method to create a preferred direction is using a spinning cylinder as the substrate, which is not always possible, especially in commercial electrospinning machines. Here, another simple technique to partly align magnetic nanofibers is investigated. Since electrospinning works in a strong electric field and the fibers thus carry charges when landing on the substrate, using partly conductive substrates leads to a current flow through the conductive parts of the substrate which, according to Ampère’s right-hand grip rule, creates a magnetic field around it. We observed that this magnetic field, on the other hand, can partly align magnetic nanofibers perpendicular to the borders of the current flow conductor. We report on the first observations of electrospinning magnetic nanofibers on partly conductive substrates with some of the conductive areas additionally being grounded, resulting in partly oriented magnetic nanofibers.

Magnetic Properties of Electrospun Magnetic Nanofiber Mats after Stabilization and Carbonization

“…Notably, polyacrylonitrile (PAN) can be spun from the low-toxic solvent DMSO [3], making the whole process relatively easy to handle and avoiding unnecessary environmental pollution. In contrast to other methods of producing magnetic nanofibers, electrospinning usually creates nanofibers with different bending radii and forms a nanofiber mat without or with only low-fiber orientation [35][36][37], resulting in much more complicated magnetic anisotropies than straight, even nanofibers [38][39][40]. This makes electrospun nanofiber mats challenging for some applications, e.g., in racetrack memory, which usually consists of an array of parallel arranged magnetic nanowires and can theoretically store data series in some ten-to hundred-domain walls per nanowire [41].…”

Adhesion of Electrospun Poly(acrylonitrile) Nanofibers on Conductive and Isolating Foil Substrates

“…Angular distributions were investigated by fast Fourier transform (FFT). The FFT images show single lines for the aligned fibers and radial diffusion patterns for the arbitrarily oriented fibers [15,20]. The ImageJ plugin Ori-entationJ [21] was used for color-coding the fibers according to their angular orientation, as well as for the analysis of the distribution of angular fiber orientation.…”

“…In previous studies, we have shown that DSSCs can be purely electrospun [11], and have investigated the influence of different foil materials on DSSC properties [12]. The main objective of this study is to investigate the adhesion of nanofibers directly electrospun onto different substrates and the influence of the conductive substrate on fiber diameter and orientation [13][14][15]. The combination of conductive foils, which contain carbon materials in particular and can thus be used as counter electrodes, with insulating nanofiber mats is highly interesting, since the latter can be used to hold liquid electrolytes [11].…”

Most recent developments in electrospun magnetic nanofibers: A review

“…In the area of neuromorphic computing, PAN nanofibers with Fe 3 O 4 and Fe 2 O 3 /NiO nanoparticles were suggested for data storage and transport. 30,124 For creation of a triboelectric nano-generator (Figure 9), Im and Park used nanofibers prepared from Fe 3 O 4 nanoparticles in PVDF. They showed that for nanofiber contents above 17%, the particles became visible outside the fibers, correlated with a decrease in the triboelectric performance.…”