The fabrication and gas sensing application of a fast-responding m-CP-PVP composite film/potassium ion-exchanged glass optical waveguide

Abstract

A m-Cresol Purple-polyvinylpyrrolidone (m-CP-PVP) composite-film was immobilized on the surface of a potassium ion-exchanged glass optical waveguide using the spin-coating method. The optical properties of the film were probed by UV-visible Spectroscopy and Fourier Transform Infrared Spectroscopy. The transmittance variation and the structural properties of the m-CP-PVP composite film/K⁺-exchanged glass optical waveguide sensor were studied before and after reaction with an amine and volatile organic gases. When the sensing film was exposed to an amine gas, the color changed from yellow to purple/blue. This simply designed sensor was able to measure trimethylamine (TMA) gas down to a concentration of 0.1 ppb at room temperature, and its response and recovery times were 1.4 s and 5.6 s, respectively.