Surface segregation of tetra- N-alkylammonium halides in formamide investigated by angle resolved electron spectroscopy

Abstract

Surface concentrations of tetra- N-alkylammonium halides in formamide have been studied using angle resolved liquid electron spectroscopy. The surface concentration is found to increase with increasing length of the alkyl groups and with increasing size of the halide ion. The distribution of (But 4N) +I − ion pairs in the surface region is calculated and described by an ion volume percentage vs. depth profile. From these profiles the surface excess of the (But 4N) +I − pairs is found to be almost independent of the bulk concentration for the investigated concentration range.