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

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 x 3 cm(2) and 4 x 4 cm(2). 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.