OBJECTIVETo prepare novel electrospun porphyrinated polyimide nanofibrous membrane for rapid detection of trace amount of methanol vapor.

METHODSPorphyrin chromophore was copolymerized into polyimide backbones and the porphyrinated polyimide nanofibrous membrane was prepared by electrospinning technique. By optimizing the processing parameters, such as solution concentration and electrospinning voltage, nanofibrous membrane with three dimensional and large surface-to-area ratio structure was fabricated for trace amount of methanol vapor sensing applications.

RESULTSThe obtained nanofibrous membrane preserved typical photophysical properties of porphyrin chromophores with uniformly fine and smooth fiber diameter. When exposed to methanol vapor, a red-shift of the absorption spectra and decrease in the emission intensities was observed, while no significant changes were seen when the membrane contacting with other common alcohols. After five times of 150 ppm methanol vapor quenching and nitrogen gas regeneration, the fluorescence of the membrane remained unchanged, indicating a good reversibility.

CONCLUSIONCombining the specific optical properties of porphyrin with large surface-area-to-volume ratio of nanofibrous membranes, a porphyrinated polyimide nanofibrous membrane has been facilely fabricated for trace methanol vapor detection. The sensing membrane exhibits good sensitivity, selectivity and reproducibility.