Ethanol Gas Sensitivity Sensor Based on Roughened POF Taper of Modified Polypyrrole Films

Abstract

The three polypyrrole (PPy) films with different mixture ratios, namely PPy1, PPy2, and PPy3, were synthesized by chemical oxidation with pyrrole and ferric chloride (FeCl3). The roughened plastic optical fiber (POF) taper assembled PPy films (POF-PPy1, POF-PPy2, and POF-PPy3) were facilely prepared and bent U shape structure for testing ethanol gas at room temperature. The morphologies of the PPy films and the roughened POF taper were studied using electron microscopy. The effect of the three PPy films on the gas response was investigated and the results showed that the POF-PPy2 exhibited a high sensitivity of 5.08 × 10−5 dB/ppm. The detection limit of the sensor was 140 ppm and its response and recovery times were 5 s and 8 s, respectively. The results also showed that as the bending radius decreased, the response and recovery times gradually shortened, while the output power increased. In addition, the proposed sensor has advantages of a low cost and simple structure.

Effect of Substrate Temperature on Porosity and Gas Sensing Properties of SnO2-B: Doped Polypyrrole Thin Films

“…The energy gap is narrowed, and the doping causes semiconduction. As a result, increasing temperature should increase the energy required for an electron in the valance band to move to the conduction band, and therefore conductivity should rise with temperature (17).The current research, however, found that the materials behave like semiconductors,the conductivity is decreasing with increase of percentage of SnO2-B dopants and conductivity is also slightly decreases as temperature increases. In the present studies, the conductance decreases for the 30% SnO2B:Ppy, because it was highly porous with energy gap 3.5 eV.…”

“…The mixture was slowly stirred for another 4 h. After that, the solution was left at room temperature for 24 h without mixing. Monomer pyrrole's polymerisation reaction with an aqueous solution of FeCl3 6H2O is a fast reaction to obtain a black precipitate (17). The resulting black precipitate was filtered and demonized water was used to rinse,then left to dry for 24 hours at ambient temperature followed by drying at 800 0 C for 10h.…”

“…Rg and Ro, respectively, are gas and air resistances (17,18). The results of the calculations for sensors fabricated during the current experiment.…”

A Comparative Study of Polypyrrole and Ag/Polypyrrole Hybrid Nanocomposites as Sensitive Material Used for New Dry Polarizable Bioimpedance Sensors

“…The mixture was slowly stirred for another 4 h. After that, the solution was left at room temperature for 24 h without mixing. Monomer pyrrole's polymerisation reaction with an aqueous solution of FeCl 3 × 6H 2 O is a fast reaction to obtain a black precipitate [38]. The black precipitate formed was filtered and washed with deionised water and dried for 24 h at room temperature, followed by drying at 80 • C for 10 h. The oxidative polymerisation reaction of pyrrole in the presence of oxidative agent FeCl 3 × 6H 2 O is described by the following reaction [30,36,38] (1).…”

“…The Ag NPs were obtained following a chemical synthesis route by reducing a tion of AgNO3 with hydrazine (the ratio of AgNO3/Hydrazine was 1/3) at a temper of 80 °C. The pale-yellow colloidal silver solution was mixed with a fresh solution of dried for 24 h at room temperature, followed by drying at 80 °C for 10 h. The oxidative polymerisation reaction of pyrrole in the presence of oxidative agent FeCl3 × 6H2O is described by the following reaction [30,36,38] (1).…”