Interaction behaviour of a PDMS-calixarene system and polar analytes characterised by microcalorimetry and...

Spectroscopic techniques and microcalorimetry were applied to investigate a polymer-(polydimethylsiloxane; PDMS) calixarene system during interaction with propylamine and n-propanol as analyte molecules. This was done to understand the sensitivity and selectivity of this system. By these means the interesting binding site of the calixarene selector was identified and dependencies on specific properties of the polymer and the functional groups were determined. Reflectometric interference spectroscopy (RIfS) was used to characterize the kinetics whereas isothermal titration calorimetry (ITC) yielded thermodynamic data. Infrared (IR) and (1)H NMR spectroscopy allowed identification of the sensing process as an interaction between the selective group of the PDMS-calixarene system and the amino group of propylamine, and measurement of the effects on hydrogen bonds. The combination of the different spectroscopic methods and the microcalorimetric measurements broadened the understanding of this system, regarded as a model system. Thus, future tailoring of functional groups designed for improved and more selective analyte detection is possible.