The monitoring of hydrocarbon vapor by electrospun PBINF modified QCM chemosensor

Abstract

Abstract This paper describes the preparation of the polybenzimidazole nanofiber (PBINF) onto the QCM sensor by electrospinning of 2,2 -(p-phenylene)-5,5 -bis(benzoxazole) (PBI) and polyvinylidene fluoride (PVDF) as the hydrocarbon sensing material for the first time. The characterization of PBINF was conducted by FTIR, SEM, TGA, AFM, and contact angle analysis. Initial experiments revealed that the higher responses were observed towards toluene and ethylbenzene vapors. The proposed chemosensor performance was then tested towards toluene and ethylbenzene vapors in different concentrations ranging from 1-10\u2009ppm-level. Hence, the chemosensor sensitivity (S, Hz ppm-1) and limit of detection (LOD, ppm) were determined as 6.7411\u2009Hz\u2009ppm-1 (toluene), 7.0743\u2009Hz\u2009ppm-1 (ethylbenzene) and 0.41\u2009ppm (toluene), 0.45\u2009ppm (ethylbenzene), respectively. Also, the adsorption phenomena were investigated by adapting the experimental results to some adsorption models. The Freundlich and Langmuir-Freundlich adsorption models were in good correlation with experimental data. Thus, it was thought that PBINF formed a heterogeneous surface, and the toluene sensing by the proposed chemosensor reached equilibria in high volatile organic compound (VOC) concentrations. In further experiments, the sensor performance was evaluated by five sequential adsorption/desorption cycles and every week for six weeks towards 10\u2009ppm toluene vapors. Hence, the chemosensor exhibited good repeatability and durability feature. It was thought that the adsorption of toluene onto the sensor surface was weak physical adsorption, such as π-π interaction between the toluene and the benzene rings in the PBI. In conclusion, the PBINF platform onto the QCM sensor will be a useful, promising agent for hydrocarbon detection in many sensing applications.