Design and Fabrication of a Fast Response Resistive-Type Humidity Sensor Using Polypyrrole (Ppy) Polymer Thin Film Structures

Abstract

In this research article, an organic polymer based polypyrrole (Ppy) composite material has been synthesized and analyzed for the design and fabrication purposes of a fast-responsive, highly sensitive, and an economical resistive-type novel humidity detection sensor. This humidity sensor most suitably serves the purpose for industrial humidity (i.e., values ranging from low to high) detection applications. First, a polypyrrole composite material (a mixture of polypyrrole, polypyrrole-NiO, polypyrrole-CeO2, and polypyrrole-Nb2O5) has been synthesized by chemical oxidative polymerization method, and then is treated at various temperatures, i.e., 100, 150 and 200 °C, respectively. After this treatment, the synthesized samples were then characterized by using FTIR, SEM, and DTA/TGA techniques for analyzing humidity sensing properties. The polypyrrole samples with the best morphological structure and properties were then incorporated on interdigitated electrodes. For the fabrication purposes of this thin film structure, at first a few drops of polyvinyl alcohol (PVA) were placed over interdigitated electrodes (IDE) and then the synthesized polypyrrole composite was uniformly deposited in the form of a thin film over it. The plots show that this is a good resistive-type humidity detection device for the relative humidity range of 30% to 90%. The response and recovery times of this newly fabricated humidity sensor were reported to be the same as 128 s at room temperature. Additionally, the stability and the repeatability response behavior of this Ppy sensor were verified up to five cycles of multiple repetitions. This presents an excellent stability and repeatability performance of the sensor. Furthermore, the capacitances versus humidity response and recovery properties of the designed sensor were studied too. This illustrates an excellent capacitive verses humidity response and shows a linear and an active behavior. Lastly, the experimental result proves that polypyrrole composite thin film shows a reasonable best performance up to a temperature of 100 °C.

Enhancing the efficiency of polypyrrole-dodecylbenzene sulfonic acid in-tube solid-phase microextraction coating for analysis of nitrogen-containing pesticides in water environments

“…In particular, dodecylbenzene sulfonic acid (DBSA), as a surfactant, not only improves the thermal and mechanical stability of PPy upon doping but also provides additional adsorption sites through its sulfonic acid group, benzene ring, and long alkyl chain, thereby enhancing its adsorption capacity for polar nitrogen-containing pesticides. In the fields of sensors and electrocatalysis, PPy, with its conjugated double bond structure, can generate π-π interactions, dipole-dipole interactions, electrostatic interactions, and hydrophobic effects, making it an ideal adsorbent for polar and ionic compounds (Hussain et al, 2021;Du et al, 2023). However, pure PPy exhibits low thermal stability (thermal decomposition temperature of approximately 230 °C) and a small surface area, limiting its application in extraction performance (Ju et al, 2022;Wu et al, 2022).…”

Humidity-Responsive Antimicrobial Membranes Based on Cross-Linked Copolymers Functionalized with Ionic Liquid Moieties

“…For instance, noncontact switches have been investigated thoroughly as smart human–machine interfaces . Significant progress has been made recently in the development of humidity actuators/sensors using various materials such as natural polymers, − synthetic polymers, − and carbon-based materials. − The selection of polymeric materials to be used for the fabrication of a humidity sensor is determined by the degree of their affinity to water and their hydrophobic properties. A fine balance is necessary to achieve the desired sensing performance, i.e., high sensitivity, rapid response, rapid recovery, and low hysteresis.…”

Multifunctional screen-printed films using polymer nanocomposite based on PPy/TiO2: conductive, photocatalytic, self-cleaning and antibacterial functionalities

“…Polypyrrole is not only one of the most extensively used conducting polymers to design bioanalytical sensors (DNA biosensors [ 36 ], immunosensors [ 37 , 38 ], SARS-CoV-2-S spike glycoprotein sensor [ 39 , 40 ], etc. ), electrochemical sensors, gas sensors (such as NH 3 , CO 2 , and CO and vapor sensing) [ 41 – 43 ], volatile organic compounds sensing [ 44 ], a layer of energy storage [ 45 ], and resistive-type humidity sensors [ 46 ], but also was used in altered fabrication such as microwave fabrication [ 47 ], pressure sensing fabrication [ 48 ], corrosion inhibitor fabrication [ 49 ] and food packaging [ 50 ].…”