PNNL

Abstract

The sorption of vapors by the selective polymeric layer on a chemical vapor sensor is described in detail and dissected into fundamental solubility interactions. The sorption process is modeled in terms of solvation parameters for vapor solubility properties and linear solvation energy relationships. The latter relationships model the log of the partition coefficient as the sum of terms related to specific types of interactions. The approaches are particularly applicable to the design and understanding of acoustic wave chemical vapor sensors such as those based on surface acoustic wave devices. It is shown how an understanding of solubility interactions informs the selection of polymers to obtain chemical diversity in sensor arrays and obtain the maximum amount of chemical information. The inherent dimensionality of the array data, as analyzed by principle components analysis, is consistent with this formulation. Furthermore, it is shown how new chemometric methods have been developed to extract the chemical information from array responses in terms of solvation parameters serving as de-scriptors of the detected vapor.