The use of polyaniline nanofiber as modified cladding for fiber optic methanol vapor sensor

A fiber optic sensor system for detection of methanol vapor was developed. The system is based on the change in the absorption of evanescent wave on core-modified cladding interface during interaction with methanol vapor. In this research, it is used polyaniline nanofiber synthesized by interfacial polymerization as modified cladding. The spectroscopy data show a specific absorbance spectrum of polyaniline nanofiber which changes in the visible range, especially in blue and red bands, when exposed to methanol vapor due to a conformational alignment of polyaniline blackbond structure. The response of the fiber optic sensor was investigated by measuring the transmission light intensity via fiber optic sensor system. It is obtained a very fast response time of 40 s and recovery time of 15 s. The fiber optic sensor also exhibits a good reversibility and repeatability.