Charge measurement of electrospun polyvinylidene fluoride fibers using a custom-made Faraday bucket

Abstract

Electrical charges on fabrics, films, and membrane materials are of scientific interest for material development and performance. In many applications, available instruments do not have sufficient sensitivity to detect variations in charge needed for scientific investigations. This paper discusses the design and construction of a custom-made Faraday bucket for measuring the charge of electrospun polyvinylidene fluoride fiber mats of sizes 3 × 3 cm2 and 4 × 4 cm2. An electrometer directly measured the change in the voltage potentials of the inner conductor of the Faraday bucket due to the insertion of fiber mat samples. The measured potentials were converted to electrical charge by modeling the Faraday bucket as a source-free resistance–capacitance circuit. The results show that the Faraday bucket was sufficiently sensitive and measured differences in the potential and charge of the fiber mats due to variations in sample size (or mass), and it detected differences in charge depending on whether the sample was taken from the center or the edges of the electrospun fiber mats.

Ultrathin Polydopamine-Graphene Oxide Hybrid Coatings on Polymer Filters with Improved Filtration Performance and Functionalities

“…Details of the setup can be found in our previous report. 32 The pristine PP filter had a negligible surface charge of −1.9 nanocoulomb (nC) (Figure 4b), and after rubbing with a latex glove for 15 s, there was an obvious increase in charge to −12.7 nC, which was due to the triboelectric effect. 50−52 After coating with an ultrathin PD, the PP-PD showed a higher negative surface charge of −12.0 nC, which was mainly attributed to the deprotonated of phenolic hydroxyl groups on PD.…”

“…A detailed description of the Faraday Bucket is given in our previous publication. 32 Briefly, the sample is slowly loaded to the interior of a metal cage, and the electrostatic charge leads to a change in the voltage relative to the surroundings (ground), which is recorded and then converted to charge with a physical model. The near infrared (NIR) irradiation was carried out using a lamp with a mixture of 850 and 660 nm wavelength light, and the irradiation intensity is approximately 85 mW/cm 2 on the sample surface.…”

Polarization of Electrospun PVDF Fiber Mats and Fiber Yarns

“…Electric charges on the fiber mat were measured using a Faraday Bucket. A detailed description of the Faraday Bucket is given in reference [12]. The fiber mats were cut to the size needed for the measurement (4 cm by 4 cm) otherwise the measurements were non-destructive.…”

“…The as-spun and polarized yarn samples were wrapped on a 'U' shaped copper wire and lowered into the Faraday bucket for measurement. The calculated charges were normalized with respect to mass of sample as discussed by Gade et al [12]. The influence of U-shaped wire holding the yarn on the measured charge was found to be negligible when the wire without yarn was lowered into the Faraday bucket and produced zero measured voltage.…”

“…Gade et al [12] fabricated a custom-made Faraday bucket and a procedure to calculate the charges of fiber mat samples. The Faraday bucket overcomes some limitations or challenges of using the methods listed in Table 1, namely: it is nondestructive, measures large sample sizes, is easy to scale-up, and has a tractable mathematical model to convert voltage to charge value.…”