Facilitated olefin transport membrane, containing positively charged silver nanoparticles (AgNPs) as olefin carriers dispersed in poly(vinyl pyrrolidone) (PVP), leads extremely high separation performances for propylene/propane mixtures. In this study, as representatives of electron withdrawing nitrobenzene compounds, 1,2-dinitrobenzene (DNB) and 3,4-dinitro toluene (DNT) were used for PVP/AgNPs membranes. The correlation between the surface charge density of AgNPs and the separation performance was investigated with X-ray photoelectron spectroscopy (XPS). A fairly good linear correlation between the surface charge density and the separation performance was confirmed, which meant that the positive charge density on the surface of AgNPs may be a key factor in determining the separation performance of facilitated olefin transport membranes.

On the basis of theory of Bratsch's electronegativity equalization, the electronegativity equalization, the group electronegativities and the group partial charges for cationic and amphoteric surfactants could be calculated using Pauling's electronegativity parameters. From calculated output, we have investigated relationships between CMC(critical micelle concentration) and partial charge and group electronegativity of hydrophilic and hydrophobic groups, structural stability of micelle for cationic and amphoteric surfactants. As a result, CMC depends upon partial charge and electronegativity of hydrophilic and hydrophobic groups for surfactants. In case of cationic surfactant, as the increment of carbon number in hydrophilic group, partial charge of hydrophilic group is increased, but CMC and electronegativity of hydrophilic group is decreased. With increasing the carbon number of hydrophilic group for cationic surfactant, its partial charge is increased, but CMC and its electronegativity are decreased. With increasing the carbon number of hydrophobic group for cationic and amphoteric surfactant, its partial charge is increased, but CMC and its electronegativity are decreased