Inverse gas chromatographic evaluation of polysiloxanes containing phenolic and fluorophenolic functional groups for use in gas sensors.

The paper presents the results of inverse gas chromatographic (IGC) research on two novel polysiloxanes: poly{dimethylsiloxane-co -[4-(2,3-difluoro-4-hydroxyphenoxy)butyl]methylsiloxane} and poly{dimethylsiloxane-co -[4-(4-hydroxyphenoxy)butyl]methylsiloxane}, dubbed PMFOS and PMOS respectively, designed for use as chemosensitive coatings for acoustoelectronic sensors. These materials contain phenolic functional substituents that differ by the presence of fluorine atoms. The materials' solvation properties were identified by IGC with application of an LSER solvation model at temperatures ranging from 40 to 120 °C. In the case of both polysiloxanes, the research revealed that the dominant type of intermolecular interaction was the formation of acidic hydrogen bonds. The material with fluorine-activated hydroxyl groups, PMFOS, is much more acidic and less basic than the other one and thus more interesting. According to LSER, PMFOS exhibits high affinity and selectivity to hydrogen bond bases. In addition, the material retains its properties even at a temperature of 120 °C.