Effect of Oil on the Solubilization in Microemulsion Systems Including Nonionic Surfactant Mixtures

Abstract

The effect of molecular weight of oil on the three-phase behavior and maximum solubilization was investigated in microemulsion systems of mixtures of di-and octaethylene glycol dodecyl ethers and mixtures of hexanol and octaethylene glycol dodecyl ether at constant temperature (25 or 35 °C). It was found that the minimum weight fraction of surfactant to make equal weights of water and oil to a single phase CXb) increases with increasing molecular weight of oil (hydrocarbon). Nonionic surfactant mainly distributes between micro-oil domains and the interface between microwater and oil domains inside the microemulsion phase. Surfactant molecules at the interface are responsible for the solubilization. Assuming that the monomeric solubility of each surfactant in oil is the same as that in the micro-oil domains of the microemulsion and the microwater domains consist of pure water, the weight fractions of each surfactant at the interface in the microemulsion (Ci or C2) were obtained by a mass-balanced equation. The mixing fraction of surfactant at the interface was also determined by another method based on the geometrical relation of the three-phase tie triangle in the composition tetrahedron. In the hexanol systems, the monomeric solubility of hexanol in water should be taken into account. Ci + C2 indicates the net solubilizing power and it dramatically decreases with increasing the molecular weight of oil.

New Trends on the Synthesis of Inorganic Nanoparticles Using Microemulsions as Confined Reaction Media

“…Although nonionic microemulsion systems are mainly affected by temperature changes, the addition of electrolytes and cosurfactant can also produce shifts in the solubilization and T HLB (hydrophilic-lipophilic balanced temperature or phase inversion temperature) of the systems (Aramaki et al, 2001;Kunieda et al, 1995;Shinoda, 1968). The use of ionic surfactants may have some drawbacks, as usually the aqueous phase uptake of ionic microemulsions is reduced in the presence of precursor salts due to screening effects, and hence microemulsion regions become smaller (Liu et al, 2000;Gianakas et al, 2006).…”

“…The film rigidity has been observed to increase with the surfactant hydrocarbon chain, whereas it substantially decreases with cosurfactant addition. The surfactant packing capacity can be also affected by the ionic strength of the droplets (Aramaki et al, 2001;Kunieda et al, 1995). The increase of surfactant molecules in the layer is proportional to the rigidity of the micelles.…”

A Novel Numerical Analysis on Surface Charge Densities of an Amphoteric O/W-Type Microemulsion in the Presence of CaCl2and/or AlCl3

“…Consequently, the unknown parameters are able to be determined by taking paper (9), we found that N is dependent on pH in the presence of a 1-1 electrolyte, because the ionization degree into account the pH dependence of N. The best fitting curves are obtained in the case of approximating that N follows the of the head groups of the DMLL molecules changes with increasing solution pH as shown by Eq. [1]. Therefore, the linear polynomial function and K Al , K Cl , and j n (n Å 0, 1, 2, 3, .…”

“…The (1-1) electrolyte (for instance, NaCl) and pH on the phase surfactant (DMLL) numbers per O/W-type microemulsion drop-behavior, the z potential, the hydrodynamic diameter, and let, i.e., the aggregation numbers, are successfully obtained as a the surface charge density of an O/W-type microemulsion To analyze this preferMicroemulsion droplets can effectively be considered to ential adsorption of Cl 0 , a new formula for the surface be ''media'' for selective solubilizations (1,2) or ''microre-charge density, containing the binding constants (K) to the actors'' for chemical reactions (3)(4)(5)(6)(7). To control the chemi-hydrophilic groups of DMLL molecules and the adsorption cal reactions or solubilization utilizing the microemulsion density (N) of DMLL molecules at the oil/water interface as precisely, the surfactant number per microemulsion droplet unknown parameters, was derived by applying electrokinetic (the aggregation number), which is one of the fundamental theory (8, 9).…”

Glycogen–Surfactant Complexes: Phase Behavior in a Water/Phytoglycogen/Sodium Dodecyl Sulfate (SDS) System

“…Since a surfactant forms various aggregates, e.g., micelles, microemulsion,5 8) and liquid crystals, 9.10) water and a water-insoluble substance can be mixed by the surfactant aggregates to offer wide applicability in colloid chemistry, e.g., pharmaceuticals and cosmetics. Various ionic surfactants, e.g., phospholipids, bile acids, and lipoproteins, exist in the human body to absorb lipids from the outside.…”