Triboelectric Response of Electrospun Stratified PVDF and PA Structures

Abstract

Utilizing the triboelectric effect of the fibrous structure, a very low cost and straightforward sensor or an energy harvester can be obtained. A device of this kind can be flexible and, moreover, it can exhibit a better output performance than a device based on the piezoelectric effect. This study is concerned with comparing the properties of triboelectric devices prepared from polyvinylidene fluoride (PVDF) fibers, polyamide 6 (PA) fibers, and fibrous structures consisting of a combination of these two materials. Four types of fibrous structures were prepared, and then their potential for use in triboelectric devices was tested. Namely, individual fibrous mats of (i) PVDF and (ii) PA fibers, and their combination—(iii) PVDF and PA fibers intertwined together. Finally, the fourth kind was (iv), a stratified three-layer structure, where the middle layer from PVDF and PA intertwined fibers was covered by PVDF fibrous layer on one side and by PA fibrous layer on the opposite side. Dielectric properties were examined and the triboelectric response was investigated in a simple triboelectric nanogenerator (TENG) of individual or combined (i–iv) fibrous structures. The highest triboelectric output voltage was observed for the stratified three-layer structure (the structure of iv type) consisting of PVDF and PA individual and intertwined fibrous layers. This TENG generated 3.5 at peak of amplitude at 6 of excitation frequency and was most sensitive at the excitation signal. The second highest triboelectric response was observed for the individual PVDF fibrous mat, generating 2.8 at peak at the same excitation frequency. The uniqueness of this work lies in the dielectric and triboelectric evaluation of the fibrous structures, where the materials PA and PVDF were electrospun simultaneously with two needles and thus created a fibrous composite. The structures showed a more effective triboelectric response compared to the fibrous structure electrospun by one needle.

A Forest‐Based Triboelectric Energy Harvester

“…Currently, electrospinning is finding applications in different areas such as healthcare and air filtration but also triboelectric nanogenerators. [41,42] The device stack is depicted in Figure 1a, where lignin and nitrocellulose (NC) fiber mats constitute the positive and negative triboelectric layers, respectively, while graphitized lignin fiber mats placed on the outer sides of the device act as electrodes. NC is typically formed by treating cellulose fibers with a mixture of sulfuric and nitric acids, resulting in the substitution of hydroxyl groups with nitrate groups (Figure 1b).…”

“…The surface charge measurements were performed by attaching a reference material (cotton cloth) to a circular weight of 100 g. Cotton is suitable as a reference material as the "zero point" as it sits close to the middle of the triboelectric series. [41,[51][52][53] The weight was put on top of the sample surface so that the reference material came in contact with the sample. This was done without applying any additional pressure besides that applied by the weight.…”

Rational Design of Advanced Triboelectric Materials for Energy Harvesting and Emerging Applications

“…[66,283] These methods are expected to be used for microspheres and hierarchically structured materials. Furthermore, multilayer assembly of electrospun materials with complementary properties can significantly improve their barrier or penetration, [81,93] and Janus film via specific electrospinning process (e.g., water-assisted electrospinning, [269] side-by-side electrospinning, [284] etc.) may realize adjustable structures that meet customizable multifunctional requirements.…”

Anisotropic Wooden Electromechanical Transduction Devices Enhanced by TEMPO Oxidization and PDMS

“…In order to improve its corrosion resistance and operation stability, many corrosion-resistant polymers had been developed for triboelectric generators. The triboelectric generators based on polydimethyl-siloxane (PDMS) and polyamide (PA) − displayed the super stability and high electromechanical efficiency.…”