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

Abstract

This study is the first report on the fabrication of polyacrylonitrile (PAN) nanofiber with rhodamine-based chemosensor (RHE) onto a mass-sensitive quartz crystal substrate using the electrospinning method and its sensing capability toward chlorinated hydrocarbons. Fabricated nanofiber webs via the electrospinning process are characterized by Fourier Transform Infrared (FTIR-ATR), Scanning Electron Microscopy, and Contact Angle measurement techniques, respectively. In order to investigate the vapor sensor properties, a Quartz Crystal Microbalance (QCM) system is employed to collect the real-time experimental data when the nanofiber sensor PAN-RHE is exposed to chlorinated hydrocarbons. Pseudo first-order and Elovich models are applied to elucidate the adsorption behavior. The morphological characterization proved smooth surface morphology without bead formation for all fibers with uniformity in the fiber skeleton. The average diameters of neat PAN and PAN nanofibers with RHE are found to be 449 and 790 nm, respectively. The nanofiber sensor PAN-RHE exhibits excellent sensing characteristics, including a high sensitivity of 0.0276 Hz/ppm, response and recovery times of 2−3 and 5−7 s, respectively, high selectivity for chloroform compared to other vapors tested, a limit of detection (LOD) of about 119.56 ppm, and a limit of quantification (LOQ) of about 362.31 ppm with a good reproducibility. The Pseudo-first-order adsorption rate and the Elovich desorption constants are determined as a function of different concentrations. The results obtained suggest that the QCM-based nanofiber sensor PAN-RHE shows great potential for the design of highly sensitive and selective chloroform sensors.