Light Scattering from Hydrophobe-Uptake Spherical Micelles near the Critical Micelle Concentration

Abstract

We have investigated aqueous micellar solutions of mixtures of a surfactant (dodecylpyridinium chloride) and a hydrophobe (1-dodecanol) near the critical micelle concentration (cmc), using simultaneous static and dynamic light scattering measurements. The static light scattering intensity for the aqueous solutions was separated into fast and slow relaxation components using dynamic light scattering results. The slow relaxation component gave us the information about the large scattering component. It turned out from this component that the amount of large colloidal particles of the hydrophobe was very tiny in the solution and hardly affects the association-dissociation equilibrium of the hydrophobe-uptake micelle. The free surfactant molecule and the hydrophobe-uptake spherical micelle in the solutions belong to the fast relaxation component. We have characterized the spherical micelle and also analyzed the association-dissociation equilibrium of the hydrophobe-uptake micelle up to near the cmc, using this scattering component extracted.

Multiple Association–Dissociation Equilibria in Solutions of Amphiphilic Molecules

“…When a solvophobic compound is added to a spherical micellar solution (e.g., oil in aqueous solution), the solvophobe may be incorporated into the solvophobic core of the spherical micelle, as shown in Figure . When the solvophobic core consists of m solvophobic tails of the surfactant and a solvophobe with volume V H , the radius of the core R core can be written as where υ R is the volume of the solvophobic tail and a R is the area of an amphiphilic molecule occupying the surface of the solvophobic core.…”

“…The hydrophobe-uptake micellization or the emulsification has been investigated for many systems ,, because hydrophobe uptake is one of the most important phenomena of micelles, which relate to extensive applications in detergents, paints, and drugs as well as potential applications to nanocarriers and nanoreactors. Therefore, many researchers were interested in the micellization and emulsification in aqueous solutions of surfactant–hydrophobe mixtures. − …”

“…Figure shows SLS and DLS results for 25 mM aqueous borax solutions of a mixture of dodecylpyridinium chloride (DPC, see Figure ) and 1-dodecanol (DOH) at 25 °C . Here, the weight fraction ξ R of DPC in the mixture is fixed to be 0.91, and the total mixture concentration c is changed as indicated in the figure.…”

“…Afterward, the theoretical arguments are applied to solutions of amphiphilic molecules, which form micelles, emulsions, and complexes as shown in Figures and . Those systems were studied by our research group ,− mainly using scattering methods. The theoretical background used to analyze the scattering results of each system is given in the Supporting Information (SI), and many symbols, association–dissociation equilibrium formula, and basic equations used to analyze light-scattering data are listed in the last section.…”

Nanostructured lipid carriers based temozolomide and gene co-encapsulated nanomedicine for gliomatosis cerebri combination therapy

“…So far, attempts have been made to simultaneously deliver genes and drugs into cancer cells, using polymeric nanoparticles (Liu et al, 2014), micelles (Morishima & Sato, 2014), nanoemulsions , dendrimers (Kaneshiro & Lu, 2009) and lipid nanoparticles to bring about satisfactory therapeutic efficiency (Tiwari & Pathak, 2011). In addition, many studies have shown that nano-sized delivery systems can reduce toxicity of drugs/genes (Shi et al, 2013;Taratula et al, 2013;Han et al, 2014).…”