A novel approach for evaluation of polymeric interface materials for chemical sensors using alternate indirect methods

摘要

The heart of a chemical sensor based on bulk or surface acoustic wave devices is a polymer-coated piezoelectric substrate that selectively sorbs and concentrates the target analyte vapors. The development of such sensors often necessitates the screening and evaluation of suitable polymeric interface materials meeting the specified sensitivity and selectivity toward the analytes of interest. The magnitude and dynamics of sorption-desorption of the vapors in the polymer and the extent of polymer-vapor interactions largely determine the performance of a sensor. The standard protocol used for the purpose is rather tedious, involving the generation and calibration of individual analyte vapors, with stringent control on temperature, humidity, and test parameters. This article outlines four different alternative techniques based on mass uptake of the analyte vapors, on its partitioning in polymers, or both, which in combination can determine the characteristics of an interface material used for coating a piezoelectric substrate in acoustic wave-based chemical sensors. These methods were applied to poly(ethylene maleate), a representative interface material. The analytes ranged from volatile organic chemicals to sarin-a chemical warfare agent-and its simulant, dimethyl methylphosphonate. (C) 2004 Wiley Periodicals, Inc. [References: 10]