FABRICATION OF POLYVINYLPYRROLIDONE (PVP) NANOFIBERS WITH CONTROLLED MORPHOLOGY AS QCM COATING MATERIALS FOR HIGH PERFORMANCES ETHANOL GAS DETECTION

• Main Author: Sukowati, Riris
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/67366
• Institution: Institut Teknologi Bandung

In this research, quartz crystal microbalances (QCM) coated PVP nanofibers with controlled morphology to enhance sensitivity ethanol sensing have been made. PVP nanofibers were deposited on the QCM surface by equalizing the mass assisted with a calibration curve using the electrospinning method to determine nanofibers morphology's effect on ethanol gas sensitivity. The fabricated nanofibers were characterized using SEM and BET. The sensor exhibited excellent sensing characteristics (high sensitivity, good selectivity, long-term stability, and good reproducibility) over a wide range of ethanol concentrations (5 - 30 ppm). The sensitivity of the spherical-beaded nanofibers (BNF) morphology sensor has the highest value (2.632 Hz/ppm) LOD/LOQ (0.018 ppm/ 0.061 ppm) compared to spindle-beaded nanofibers (SBNF) morphology (1.878 Hz/ppm), LOD/LOQ (0.025 ppm/0.085 ppm), and pure nanofibers (PNF) (1.151 Hz/ppm), LOD/LOQ (0.041 ppm/0.139 ppm) which has the lowest sensitivity. The BNF sensor also shows the best sensor response to ethanol compared to other samples. By equating the mass deposited on the QCM surface, the result shows that the morphology of Spherical-beaded nanofibers is more sensitive than the morphology of pure nanofibers. Moreover, the adsorption isotherm models of the sensor were studied to validate the physical adsorption affinity towards ethanol by applying Langmuir, Freundlich, Scatchard, and Langmuir-Freundlich isotherm models. The high sensitivity of PVP nanofibers towards ethanol gas could be attributed to hydrogen bonding. The results of this study can be a promising way to enhance the sensitivity of QCM sensors modified with polymers using the morphology of beaded fiber which is still rarely done.