This project involves an entirely new sensor concept for monitoring the presence, concentration, and reactions of a wide variety of chemical species, including organic solvents, salts, and biological chemicals. This sensor design exploits the acoustical properties of symmetric multilayers placed on a piezoelectric transducer. These properties are extremely sensitive to changes in layer density, thickness, and elastic constants, all of which are functions of the molecular state. The symmetric multilayer materials used would be a class of bioelastic polymers which are capable of converting many forms of chemical reaction energy into changes affecting the molecular state. The major advantages of the planned sensor are its sensitivity, versatility, and chemical specificity. The Phase I effort will be to design, fabricate, and test a prototype sensor utilizing bioelastic polymeric materials. This would involve the selection of a polymer for a specific chemical reaction, e.g., one that is pH sensitive, or one that is sensitive to the presence of a salt or an organic solvent. Anticipated Results/Potential Commercial Applications as described by the awardee: The outcome of this project should be a new type of acoustical sensor which utilizes bioelastic polymers for a wide variety of chemical measurements. The device would be in expensive, rugged, and capable of in-situ chemical monitoring in a non-laboratory environment.