Impedance Behaviour of a Microporous PMMA-Film ‘Coated Constant Phase Element’ based Chemical Sensor

Abstract

Abstract-In this work, it has been attempted to characterize a new type of impedance sensor called constant phase element (CPE) sensor; which has microporous PMMA-film coating on the electrode surface. It has been shown that the 'constant phase angle (CPA)' behaviour is primarily due to the porous structure of the electrode surface. And the phase angle at the output of the sensor changes with thickness variation of the PMMA coating and ionic property of the medium in which the sensor is dipped in. The sensor has been used for chemical sensing.A phase angle detector circuit gives the output in voltage with the change in the phase angle.The complex impedance plots of the probes has also been discussed. The important fact is that the constructed CPE gives rise to a fractional order system.

A Novel Sol–Gel Thin-Film Constant Phase Sensor for High Humidity Measurement in the Range of 50%–100% RH

“…The CPS has been fabricated slightly in different ways as reported in the literature [1], [6], [9]. Instead of using polymythayl metha accrylate (PMMA) insulating film, aluminum oxide film because of its chemical inertness and thermal stability has been used [6].…”

“…Constant phase behavior is not well understood, some researchers in the analytical chemistry have reported that this phenomenon is observed at metal-insulator interface in polarizing medium such as water [7], [8]. The CP behavior of CPS arises due to porous nature of the insulating film and the pore morphology of the film has significant effect on the parameters such as the fractional exponent and the amplitude [9]. CP behavior has also been reported due to nonuniformity and porous nature of the interface electrode [7].…”

“…Nanostructured ceramic humidity sensors are widely used to fulfill the application needs in different ranges due to their chemical inertness, mechanical strength and large working temperature [12], [13], [15]. Relative humidity sensor is conventionally fabricated by porous ceramic, porous silicon, polymer or electrolytic type materials [9], [10], [12].…”

Multivariate theory‐based passivity criteria for linear fractional networks

“…As the base of the fractional‐order circuit theory, the fractional‐order elements, also known as constant phase elements, have been deeply explored, and many ingenious methods were reported to realize them, including the self‐similar RC tree circuit and grid‐type RC ladder circuit for 0.5‐order approximation, the PMMA film‐coated capacitive probe, and the fractal structure on silicon . Besides, many other novel fractional‐order elements have also been proposed, such as fractional‐order mutual inductor, fractional‐order 2‐port, and fractional memristor .…”

“…9 Within the field of electrical and electronic engineering, plenty of components and equipment are modeled more neatly and precisely with the aids of fractional calculus in the light of their fractional essences, including the lead-acid batteries, 10,11 lithium-ion batteries, 12,13 supercapacitors, 14,15 PN junction diodes, 16 Buck-Boost converters, 17 transmission lines, 18 and transformers. 19 As the base of the fractional-order circuit theory, the fractional-order elements, also known as constant phase elements, have been deeply explored, and many ingenious methods were reported to realize them, including the selfsimilar RC tree circuit and grid-type RC ladder circuit for 0.5-order approximation, 20 the PMMA film-coated capacitive probe, 21 and the fractal structure on silicon. 22 Besides, many other novel fractional-order elements have also been proposed, such as fractional-order mutual inductor, 23 fractional-order 2-port, 24 and fractional memristor.…”