Study on Selectivity Enhancement of Tin Dioxide Gas Sensor Using Non-conducting Polymer Membrane

摘要

Non-conducting polymer membrane can be used as molecular sieve to enhance the selectivity of tin dioxide gas sensor. A commercial polymer, polyimide XU218 of Eiba-Geigy company, is coated on the surface of a tin dioxide gas sensor FIGARO TGS842 which was designed to detect methane. The polymer coated sensor is calibrated in a high accuracy testing system which is controlled by PC with GPIB and mass flow controllers (MFCs). Three gases, hydrogen, methane, and ammonia, are used to investigate the response of the sensor. It is found that the sensor shows a characteristic change in response to ammonia and almost negligible change in response to hydrogen and methane.