Design Selective Gas Sensors Based on Nano-Sized Polypyrrole/Polytetrafluoroethylene and Polypropylene Membranes

Some selective gas sensors based on nano-sized polypyrrole (PPy) fiber surrounded with polytetrafluoroethylene (teflon) and polypropylene membranes (PPy-m) were constructed. Two membranes, including polytetrafluoroethylene and polypropylene membranes, were used to surround polypyrrole fibers. Polypyrrole fiber (PPy-f) samples have been prepared by polymerization of pyrrole on the surfaces of the polyester and polytetrafluoroethylene fibers in the presence of an oxidizing agent at solution and vapor phase. The morphology of the resulting PPy on the polyester and polytetrafluoroethylene fibers was analyzed by scanning electron microscopy. The effects of the used membrane type and a substrate type of fiber on the conductivity and response patterns of the PPy-m as a gas sensor to the different gasses were studied. The PPy-m gas sensors demonstrated fast response time (<;1 s). The sensitivity of the PPy-m gas sensor for various volatile organic compounds was also reported. The PPy-polyester-teflon membrane exhibits a good selectivity to the methylamine and could also be successfully applied as a highly selective sensor for detection of methylamine (DL = 100 ng). The linearity of the calibration curve was observed in the range of 0.5-60 μg. The PPy-polyester-polypropylene exhibits a good selectivity to the dimethylformamide (DMF). The detection limit of this sensor for DMF is 0.6 μg. The linearity of the calibration curve was observed in the range of 4-100 μg.