RESPONSE OF A POLY(PYRROLE) RESISTIVE MICRO-BRIDGE TO ETHANOL VAPOR

In this paper the authors describe the behaviour of a silicon micro-br idge fabricated with four conducting polymer resistive elements (two a ctive) in a CMOS-compatible process. The poly(pyrrole) (PPy) bridges w ere characterised using a precision analogue interface circuit with th e constant-current drive and voltage off-set set by a Labview Virtual Instrument. The responses of eight polymer micro-bridges to ethanol va pour were recorded at different temperatures and humidity's. The outpu t voltage of the bridge circuit followed the classical Langmuir adsorp tion isotherm in concentration and generally fell with increasing temp erature and humidity. A typical bridge sensitivity to ethanol of ca. 3 0 mu V/ppm was observed at room temperature with the linear temperatur e coefficient of the operation being relatively high at - 2.8 x 10(-2) /degrees C. (C) 1998 Elsevier Science S.A. All rights reserved.