Sensitivity of polypyrrole sensor with different oxidizing agents

Polyoyrrole has attracted much interest as sensing materials because it shows the advantages of good sensitivities, optimum performance at room temperature, and response to a wide range of organic gases. Polypyrrole is known to have different electronic band structure according to degree of oxidation. In this study, ferric chloride and APS (Ammonium persulfate) was used as oxidizing agents to compare sensing characteristic according to degree of oxidation. Polymerization progress with DBSA (dodecylbenzensulfonic acid) as a dopant at 0 °C, 1 atm. Polymer films were prepared by screen printing method on the alumina substrate having interdigitated electrodes for the gas sensor application. In the case of electrical response, the sensitivity for toluene, benzene, ethyl benzene and xylene was measured by flow system equipped with mass flow controllers, detection chamber. The gas sensors using APS as oxidizing agent show positive sensitivity, while the sensors using FeCl₃ as an oxidizing agent show negative sensitivity.