Salt-induced transition from a micellar to a lamellar liquid crystalline phase in dilute mixtures of anionic and nonionic surfactants in aqueous solution

• Published in: Langmuir Vol. 9; no. 7; pp. 1714 - 1720
• Main Authors: Sein, Arjen, Engberts, Jan B. F. N, van der Linden, Erik, van de Pas, John C
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.07.1993
• Subjects: 02 PETROLEUM; 020300 - Petroleum- Drilling & Production; 400201 - Chemical & Physicochemical Properties; AGGLOMERATION; Chemistry; CRYSTALS; ENHANCED RECOVERY; Exact sciences and technology; FLUIDS; General and physical chemistry; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; LAMELLAE; LIQUID CRYSTALS; LIQUIDS; MICELLAR SYSTEMS; SALTS; Surface physical chemistry; Surface-active agents: properties; SURFACTANTS; Alkali metal Compounds; Particle size; Electrolyte solution; Non ionic surfactant; Citrate; Micelle; Ether polymer; Experimental study; Electron microscopy; Bilayer; Phase transitions; Fluorescence spectrometry; Sulfonate; Aggregation; Sodium Compounds; Anionic surfactant; Lamellar structure; Concentration effect; Turbidity; Benzenic compound; Spherical particle
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la00031a018

In dilute mixtures of anionic surfactant, sodium dodecylbenzenesulfonate (NaDoBS), and nonionic poly(ethylene oxide) alkylmonoether (C[sub 13-15]E[sub ]) a transition from a micellar to a lamellar phase is found at high salting-out electrolyte (NaCit) concentrations. With an increase of the salt concentration, different types of lamellar aggregates are formed. The existence of different types of aggregates is reflected by changes of the turbidity of the solutions. Light and fluorescence microscopy, freeze-fractured electron microscopy, confocal scanning laser microscopy (CSLM), and fluorescence depolarization were employed to characterize the aggregates and to induce a mechanism for the transition from a micellar to a lamellar phase. Surfactant aggregation is important in view of possible applications in enhanced oil recovery. 39 refs., 10 figs.