SOLUBILITY INTERACTIONS AND THE DESIGN OF CHEMICALLY SELECTIVE SORBENT COATINGS FOR CHEMICAL SENSORS AND ARRAYS

A continual challenge in the field of chemical detection is the development of approaches to designing microsensors and microsensor-based detectors with high selectivity. No single science exists to unite all sensor technologies with a common set of principles and a common approach to achieving selectivity. Nevertheless, in the area of vapor detection, sorption phenomena and solubility interactions can be identified as common features of many sensors. In designing microsensors for vapor detection, interactive coating materials must be chosen that will collect and concentrate analyte molecules at the sensor's surface. The sensitivity and selectivity of each individual sensor is controlled by tailoring the chemical and physical properties of the coating material to maximize particular solubility interactions. The selection of coatings for the complete sensor array is logically made through a systematic variation of the solubility properties of the coating materials, so that each sensor is selective for a different balance of solubility interactions. This account discusses solubility in great detail. Parameters and methodologies for characterizing analyte solubility properties, sensor coating material solubility properties, and their interactions are presented. Specific functional groups are recommended for inclusion in sensor coating materials in order to maximize particular interactions. In addition, the treatment of coating material properties is integrated with consideration of the factors that influence chemical selectivity in sensor arrays. Methods for choosing coatings intelligently for sensor arrays, and for optimizing sensor arrays for particular analytes are considered.