APPLICATION OF ORGANIC SUPRAMOLECULAR AND POLYMERIC COMPOUNDS FOR CHEMICAL SENSORS

The bulk dissolution of solvent molecules into polymeric thin layers leads to characteristic sensor signals of quartz microbalance, thermopile, optical and interdigital capacitor transducers. As the result of different molecular interactions, the modification of polymers such as polysiloxanes with polar cyano groups, polarizable phenyl groups, as well as acidic and basic groups leads to specific variations of selectivities and sensitivities if compared with the non-modified polymers. This makes possible a systematic tailoring of polymers for specific applications. Layers of organic supramolecular compounds like calixarenes make use of very specific key/lock interactions with organic solvent molecules if their molecular recognition structures have optimized ring sizes, and substituents, and if these interaction sites are accessible from the gas phase. This follows from experiments and theoretical force field calculations. Pronounced differences exist between the structures of recognition sites in the two model systems which range from well-defined time-independent 'static' geometries in calix[4]arenes to time-dependent 'fluctuating' geometries in polysiloxanes.