Electrospun Polyacrylonitrile Nanofibers Mixed with Citric Acid as a Quartz Crystal Microbalance Ammonia Vapor Sensor

Abstract

The detection of ammonia vapor in the air is always challenging and in great demand, with the main issues are their low sensitivity. In this contribution, we developed a quartz crystal microbalance (QCM) gas sensor to detect ammonia vapor in the air using electrospun polyacrylonitrile (PAN) nanofiber mixed with citric acid (CA) as its sensing material. The nanostructured morphology of the as‐prepared nanofiber sensors was confirmed using scanning electron microscopy (SEM), while the existence of the CA in the PAN/CA nanofiber confirms using Fourier transform infrared (FTIR) spectroscopy. The average diameter of the PAN and PAN/CA nanofiber sample was found in the range of 260 nm to 307 nm. The highest sensor sensitivity was obtained by the PAN/CA4 nanofiber sensor with the value of 0.28 Hz/ppm, increasing almost 4 times compared to the unmodified PAN nanofiber sensor (0.075 Hz/ppm). Moreover, the sensor also shows good reversibility, fast response/recovery time, and excellent repeatability sensing performance. The addition of CA into the PAN nanofiber structures enhances the sensor sensitivity, probably due to the enrichment of carboxyl group at the sensor surface. This work could become a promising and alternative way to enhance the sensitivity of a QCM gas sensor modified with polymers doped with suitable compounds.

Influence of dopant concentration on the ammonia sensing performance of citric acid-doped polyvinyl acetate nanofibers

“…The LOD values of several devices were not mentioned. 96,98,100–102 All in all, it has been proven that the NF CA sensors exhibit good ammonia sensing performance, in which their improvement can be achieved by increasing the dopant concentration of citric acid.…”

“…The LOD values of several devices were not mentioned. 96,98,[100][101][102] All in all, it has been proven that the NF CA sensors exhibit good ammonia sensing performance, in which their improvement can be achieved by increasing the dopant concentration of citric acid. The developed CA-doped PVAc nanober ammonia sensors have potential to be employed as one of the key components in portable electronic noses, in which all the sensing chamber, air sampling components, ltering module, and calibration system need to be miniaturized and integrated into a small housing.…”

Rhodamine-Based Electrospun Polyacrylonitrile (PAN) Nanofiber Sensor for the Detection of Chlorinated Hydrocarbon Vapors

“…Adding citric acid to PAN improved the sensitivity value of the PAN/CA QCM sensor by an increase of 4 times higher than that of the PAN QCM sensor. 3 In addition, our previous study with a PAN nanofiber-based QCM sensor 40 showed a response to chlorine compounds and adding poylpyrole (PPy) to the PAN structure as a (PAN)/polypyrrole (PPy) nanofiber film improved the stability of the QCM sensor. 41 The study of adsorption dynamics is one of the main issues to understand the interaction nature between the sensing material and target organic vapor molecules.…”

“…Remarkable industrial advances, fast technological applications, and fast urbanization have caused a rapid increase in the amount of volatile organic compounds (VOCs) in human life, resulting in significant environmental contamination and human health hazards. VOCs are one of the most important problems for people living indoors due to their acute and chronic toxicity. , They are a significant class of atmospheric pollutants due to their critical chemical properties, such as a high vapor pressure at ambient temperature, high reactivity, volatility, and toxicity . Owing to these factors, organizations, such as the World Health Organization and the Environmental Protection Agency, have issued guidelines to limit the concentration of VOCs in indoor and workplace environments.…”

“…While system parameters are viscosity, conductivity, and surface tension of the polymer solution, flow rate determination and applying electrical power to polymer blend are also processing parameters affecting the fiber diameter during fiber deposition onto the surface. Nanofibers are widely used in different areas, such as environmental engineering, biomedical engineering, tissue engineering, and mechanical engineering, due to high porosity, large surface area to volume ratio, good chemical and physical stability, and fast adsorption capabilities. − Electrospun PAN-based nanofibers, such as PAN, − polyacrylonitrile (PAN)/polypyrrole (PPy), the PAN/CA, are used for VOCs detection using the QCM method. Febrina et al showed that QCM-based PAN nanofiber sensors yielded a sensor response to various VOCs.…”