Implementation of PVA-Nanofibers Heat Absorption Monitoring Sensor for Ultrasensitive Detection of 2,4-Dinitrotoluene

In this paper, a PVA-nanofibers heat absorption monitoring (PVA-HAM) sensor is fabricated by developing the HAM sensor to detect 2,4-Dinitrotoluene (DNT). Polyvinyl alcohol (PVA) has a high melting point, electrospinning capability, and ability to form the hydrogen bond with DNT. Thus, a thin layer of PVA nanofibers is implemented on the active area of the sensor through electrospinning method, which improves the absorption ability and the sensitivity of the PVA-HAM sensor due to the formation of the hydrogen bond between PVA and DNT molecules, as well as the huge surface to volume ratio of PVA nanofibers. Uniform nanofibers with the average fiber diameter of 97 nm can be obtained using 9.1 wt% PVA solution and controlling electrospinning conditions. The surface morphology of PVA-HAM sensor demonstrates that the absorption area has increased 3.87 times compared with bare HAM sensor. Experimental results show that the PVA-HAM sensor is able to detect DNT about 13.27 ppb in 80 ms, which indicates that the limit of detection has improved 3.77 times than the bare sensor. In addition, the fabricated sensor has high repeatability and reproducibility, and also it has a good selectivity to DNT compared to common volatile chemicals.