Swelling Behavior of Lamellar Phases with Calcium Dodecyl Sulfate, Heptanol or Octanol, and Water

Abstract

The swelling behavior of calcium dodecyl sulfate (CDS)/water with heptanol and octanol was investigated at 25°C. Both systems form a condensed lamellar phase at a high content of surfactant and cosurfactant and a highly swollen lamellar phase at a low surfactant content. There is no single-phase channel between both lamellar regions. A dilute L3 phase exists in the heptanol system as well as in the octanol system. This L3 phase is water-like transparent and shows no streaming birefringence. On dilution of samples with an appropriate composition of water, iridescent phases can be obtained which display bright blue to green colors. In contrast to CDS with pentanol or hexanol, the lamellar region is broken into a dilute phase and a condensed phase because of decreasing undulation forces of systems containing longer chain alcohols.

Self-assembly of metal–ligand coordinated charged vesicles

“…Anionic surfactants with multi-valent metal counterions have high Krafft points which make them hardly dissolve in water and exhibit very simple phase behaviors in solution at room temperature. However, when they are mixed with nonionic surfactants or cosurfactants, the rich sequence of phases can be observed, forming diverse aggregates such as micelles, novel sponge phase (L 3 -phase), and the lamellar phase with high swollen capability [34][35][36][37][38]. The aggregation behaviors of Ca 2+ -surfactants with additives were reviewed by H Hoffmann et al [39 • ].…”

Effect of Hydrophilic Groups of Ca Surfactants and Hydrophobic Chains of CnDMAO on Coordinated Vesicle Formation

“…28 However, when mixed with nonionic surfactants or cosurfactants, diverse aggregates are obtained. [28][29][30] Among these systems, the formation of vesicles is found to be facile in mixtures of multivalent *Corresponding author. E-mail: songaixin@sdu.edu.cn.…”

“…Another typical route is to form metal−ligand coordinated systems. − Surfactants with multivalent metal counterions usually have high Krafft points and are hardly dissolved in water, which induces very simple phase behaviors in aqueous solutions at room temperature . However, when mixed with nonionic surfactants or cosurfactants, diverse aggregates are obtained. − Among these systems, the formation of vesicles is found to be facile in mixtures of multivalent metal surfactants and C 14 DMAO, driven by metal−ligand coordination between the divalent or multivalent metal ions and N → O groups of C 14 DMAO. − In these systems, metal ions are tightly associated with the headgroups of surfactants, constructing vesicle membranes, which are not shielded by excess salts. The aggregates formed can be used as templates for preparing nano- or micromaterials because of the fixation of metal ions on the bilayer membranes, which can be precipitated through different reactions. , A series of metal−ligand complexes formed between C n DMAO and anionic surfactants with multivalent metal ions (Zn 2+ , Ca 2+ , Ba 2+ , Al 3+ , etc.)…”

Investigation of the L3 Phase in Systems Containing Calcium Dodecyl Sulfate, Alcohol, and Water

“…Studies of the L 3 phase have attracted considerable attention in the past years. The term “L 3 ” has been used since 1984 for “anomalous isotropic phases” that are located above swollen lamellar phases at higher cosurfactant concentrations. ,, The L 3 phase typically has a low viscosity and exhibits strong light scattering and streaming birefringence. − It can be described as a sponge phase consisting of a bicontinuous network of highly interconnected nonoriented surfactant bilayers. − This structure has been predicted theoretically, the stabilizing factors being entropic effects. , A typical L 3 phase behavior was reported in the short-chain unshielded ionic system of sodium octanoate/octanoic acid/water as early as 1969 . The L 2 phase extends into the water corner in a narrow channel.…”