RESPONSE KINETICS OF POLYMER-COATED BULK ACOUSTIC-WAVE DEVICES ON EXPOSURE TO GASES AND VAPORS

The response of bulk acoustic wave (BAW) devices coated with various polymeric materials to step changes in vapour concentration is shown to be modelled accurately by the sum of two exponentials. It is apparent that the parameters of the exponentials are dependent upon both the coating material used and the gas or vapour present. An automated method of fitting the response kinetics is described. This is shown to allow characterisation of the sensor's response before steady state is reached and to provide additional information for classification of the analyte.