Effect of the Head Group of Surfactant on the Miscibility of Sodium Chloride and Surfactant in an Adsorbed Film and Micelle

Charge number effect on the miscibility of inorganic salt and surfactant in adsorbed film and micelle: Inorganic salt–octyl methyl sulfoxide mixtures

“…OMS is the same sample as that used in the previous study [7]. CaCl 2 (JIS special grade reagent) purchased from Wako Pure Chemical Industries, Ltd. and LaCl 3 (99.9%) from Aldrich Chemical Company, Inc. were dried at 200 • C for 12 h under reduced pressure and used without further purification.…”

“…Miscibility of OMS with the two salts in the adsorbed films and micelles obtained from the surface tension measurement is compared to the corresponding one with NaCl in the previous study [7].…”

“…Slight attractive interaction between Na + ion and nonionic surfactant molecule and repulsive interaction between Na + ion and surfactant cation were observed in the adsorbed films and micelles [5][6][7][8].…”

“…Effect of added inorganic salts on the solution properties of surfactants has been studied in terms of salting-out and salting-in, in relation to the solubility of surfactant and the molecular and ionic interaction in solution [1][2][3][4]. However, we have applied the thermodynamic treatment of surfactant mixture to the mixtures of inorganic salt and surfactant from the standpoint of mixed adsorption and micelle formation [5][6][7][8].…”

Interaction between cationic and conventional nonionic surfactants in the mixed micelle and monolayer formed in aqueous medium

“…The origin of the interaction between ionic and nonionic surfactants in adsorbed films and micelles was investigated by applying the thermodynamic treatment of surfactant mixtures to the mixtures of inorganic salt and nonionic surfactant 27,28 and to those of nonionic and ionic surfactants with different ionic head groups and counter ions. 29 It is concluded from those studies that: the polar head group of nonionic surfactant attracts inorganic cations in adsorbed films and micelles and a large difference in the size of head group between ionic and nonionic surfactants is favorable for the packing of the surfactants in adsorbed films and micelles, and a counter ion with a large hydration radius is less effective than that with a small hydration radius for the shielding of the charge on the ionic head group of surfactant in adsorbed films and micelles and causes large interaction between the head groups of ionic and nonionic surfactants.…”