A Simple Route to Prepare Polypyrrole-Coated Filter Papers via Vapor Phase Polymerization and Their Gas Sensing Application

Abstract

Vapor phase polymerization has been used for the synthesis of polypyrrole-coated filter paper (PPy-FP) using a simple experimental setup. In addition, we have doped the polymer-coated filter papers with hydrochloric acid (HCl), camphorsulfonic acid (CSA), and p-toluenesulfonic acid (PTSA) to prepare HCl-PPy-FP, CSA-PPy-FP, and PTSA–PPy-FP, respectively. These samples were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR), energy dispersive X-ray (EDX) analysis, and powder X-ray diffraction (PXRD) techniques. The prepared PPy-coated filter papers have been used for ammonia vapor sensing studies at room temperature. The sensing device of the hybrid filter papers was developed by pasting Cu strips as electrodes. It has been observed that doping enhances the conductivity from 1.78 × 10–5 to 3.34 × 10–5 S/cm. The sensing performance also improved on doping, and among the developed sensors, HCl-PPy-FP shows the best result. The limit of detection (LOD) value for PPy-FP is found to be 13 ppm, which has been improved up to 5.2 ppm for HCl-PPy-FP. Doping increases the delocalization along the PPy chain to generate more active sites. The fabricated devices are flexible, easy to handle, and cost-effective.

Synthesis and factor affecting on the conductivity of polypyrrole: a short review

“…The term VPP is used interchangeably with vapor deposition polymerization 95 . Majumdar et al 96 and Hanif et al 97 described VPP as an easy, inexpensive, and effective method of depositing CP coating onto a particular substrate. The main advantage of VPP is that it is a solvent‐free synthesis in which the monomers are applied as vapor rather than a solution, and no liquid acts as transport medium for particle agglomeration 94,95,98 .…”

“…The PPy‐coated fabrics show a surface resistance of 0.5–0.8 kΩ/cm. Meanwhile, Majumdar et al 96 fabricated PPy‐coated filter paper (FP) doped with HCl, CSA, and PTSA by using VPP method. Initially, FP (substrate) is soaked in 0.1 M FeCl 3 solution for 15 min followed by drying at room temperature.…”

“…The dopants are generally added into the polymers to improve their electrical conductivity and capacitive performance 138 . Various types of dopants can be used to enhance PPy conductivity, for instance, BSNa, NSA, TsONa, HCl, itaconic acid (IA), and fumaric acid (FA) 14,96,126 . Moreover, surfactants such as NaDBS and SDS also found to be able to act as dopants in the polymerization of PPy 77,139 …”

“…PPy films doped with IC demonstrated are found to have lower conductivity (0.0002 S/cm) than PPy films doped with KC (0.0007 S/cm), respectively. Majumdar et al 96 evaluated the effect of different dopants (HCl, CSA, and PTSA) on the conductivity of PPy film coated onto FP substrate. Results demonstrate that the conductivities of PPy film increase from 1.78 × 10 −5 S/cm (undoped) to 3.34 × 10 −5 , 2.49 × 10 −5 , and 2.30 × 10 −5 S/cm with the use of HCl, CSA, and PTSA dopants, respectively.…”

Copper Fluoride Doped Polypyrrole for Portable and Enhanced Ammonia Sensing at Room Temperature

“…et al explored the effect of inorganic and organic acid dopants on ammonia and other VOC sensing performance of PPy nanoparticles coated filter papers. [19] According to the experimental facts, research groups revealed that the nature of electrolyte solution and salt concentration during PPy polymerization also play a pivotal role in the ammonia sensing phenomenon. [20] Most of these researchers introduced the PPy as a selective solid-state sensor material and humidity doesn't affect the measurement of ammonia.…”