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 p olymeric 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 c oating material used and the gas or vapour present. An automated metho d of fitting the response kinetics is described. This is shown to allo w characterisation of the sensor's response before steady state is rea ched and to provide additional information for classification of the a nalyte.