Solution behavior and solid phase transitions of quaternary ammonium surfactants with head groups decorated by hydroxyl groups

Lamellar Tetragonal Symmetry of Amphiphilic Thermotropic Ionic Liquid Crystals in the Framework of Other Closely Related Highly Ordered Structures

An overview of the chemical compounds forming the rare smectic T phases is presented with references to the historical context. Thermodynamics (transition temperatures, enthalpies) along with the factors (stereochemical constraints, electrostatic interactions, aliphatic chain stacking, intermolecular forces) contributing to the adoption of tetragonal scaffolds are also discussed. Characteristic optical microscopy textures and X-ray diffraction patterns are presented. In parallel, a comparison of the geometrical parameters such as distances between atoms, molecular areas, volumes, and lattice parameters with the closest two-dimensional and three-dimensional organizations, is performed.

Ionic-surfactants-based thermotropic liquid crystals

Ionic surfactants can be combined with various functional groups through electrostatic interaction, resulting in a series of thermotropic liquid crystals (TLCs).

Aggregate evolution in aqueous solutions of a Gemini surfactant derived from dehydroabietic acid

Innovations in surfactant structure are a feasible way to probe molecular self-assembly principles. Herein, the solution behaviour of a newly synthesized Gemini surfactant derived from dehydroabietic acid, abbreviated R-(EO)-E-R, was investigated using surface tension, fluorescence, isothermal titration calorimetry (ITC), rheology, freeze-fracture transmission electron microscopy (FF-TEM) and cryogenic transmission electron microscopy (cryo-TEM) methods. R-(EO)-E-R has two large, rigid hydrophobic groups. At low concentrations, R-(EO)-E-R forms micelles with an aggregation number of approximately 10, which is smaller than those of Gemini surfactants containing flexible alkyl tails. In addition, the micellization process is less exothermic because of the rigidity of the hydrophobic portions. As the concentration increases, R-(EO)-E-R without any additives forms wormlike micelles, endowing the solution with an obvious viscoelasticity. Further increases in the concentration lead to the coexistence of single-walled vesicles, double-walled vesicles and rarely observed long, tubular vesicles. This behaviour is attributed to the two large, rigid hydrophobic groups of R-(EO)-E-R, which increase the density of the hydrophobic portion around the ionic head groups and facilitate the formation of aggregates with lower curvatures and asymmetric morphology. Surfactants containing rigid hydrophobic portions are expected to result in more delicate, self-assembled morphologies with broad applications.

Ionic liquid crystals with novel thermal properties formed by the gemini surfactants containing four hydroxyl groups

The ionic liquid crystals formed by the gemini surfactants containing four hydroxyl groups show sustained-release behavior of phase enthalpy.

Synthesis and Colloidal-Chemical Properties of Surfactants Based on Alkyl Amines and Propylene Oxide

Octyl amine, nonyl amine, dodecyl amine, hexadecyl amine and octadecyl amine are propoxylated with propylene oxide at mole ratios 1 : 1 and 1 : 2. The structure of the synthesized compounds has been identified by IR-and NMR-spectroscopy methods. Colloidal-chemical indices of these compounds have also been determined and their surface-active parameters have been measured, including the critical micelle concentration (CMC), the effectiveness of surface tension reduction (πCMC), the surface excess concentration (Γmax), area per molecule at the interface (Amin), the changes of Gibbs free energies of adsorption (ΔGad) and micellization (ΔGmic). Petroleum-collecting and petroleum-dispersing capacities of the synthesized compounds on the surface of water of varying mineralization degree have been studied.

Properties and sodium salicylate induced aggregation behavior of a tail-branched cationic surfactant with a hydroxyl-containing hydrophilic head

This paper introduced a cationic amphiphile with remarkable surface activity, whose aggregation behavior could be modulated by salt addition.

Synthesis and properties of quaternary ammonium surfactants containing a methoxy benzyl substitute

m-MDRA-n exhibit high surface activity, excellent adsorptive and bacterial properties, thermodynamic functions of micellization for m-MDRA-n were researched.