TETRABUTYLAMMONIUMIODIDE IN FORMAMIDE AND HYDROXYPROPIONITRILE - THE TEMPERATURE-DEPENDENCE OF SEGREGATION STUDIED BY METASTABLE INDUCED ELECTRON-SPECTROSCOPY

Metastable induced electron spectroscopy is used to investigate the surface segregation of tetrabutylammoniumiodide in the solvents formamide and hydroxypropionitrile. In formamide no temperature dependence of the amount of salt found in the topmost surface layer can be traced. The segregation in hydroxypropionitrile is favoured by low solvent temperatures. Comparing the given bulk concentration with the particle ratio in the surface shows a larger enhancement in formamide. With the aid of surface tension measurements and under the assumption of a simple depth profile it is possible to estimate the thickness of the surface layer with an enhanced salt concentration.