Physicochemical Properties of α-Form Hydrated Crystalline Phase of 3-(10-Carboxydecyl)-1,1,1,3,5,5,5-heptamethyl Trisiloxane/Higher alcohol/Polyoxyethylene (5 mol) Glyceryl monostearate/Water System

Abstract

The α-form hydrated crystalline phase (often called as an α-gel) is one of the hydrated crystalline phases which can be exhibited by surfactants and lipids. In this study, a novel system of an α-form hydrated crystal was developed, composed of 3-(10-carboxydecyl)-1,1,1,3,5,5,5-heptamethyl trisiloxane (CDTS), polyoxyethylene (5 mol) glyceryl monostearate (GMS-5), higher alcohol. This is the first report to indicate that a silicone surfactant can form an α-form hydrated crystal. The physicochemical properties of this system were characterized by small and wide angle X-ray scattering (SWAXS), differential scanning calorimetry (DSC), and diffusion-ordered NMR spectroscopy (DOSY) experiments. SWAXS and DSC measurements revealed that a plurality of crystalline phases coexist in the CDTS/higher alcohol/water ternary system. By adding GMS-5 to the ternary system, however, a wide region of a single α-form hydrated crystalline phase was obtained. The self-diffusion coefficients (D) from the NMR measurements suggested that all of the CDTS, GMS-5, and higher alcohol molecules were incorporated into the same α-form hydrated crystals.

Structural Change of an α-Gel (α-Form Hydrated Crystal) Induced by Temperature and Shear Flow in an Oleic Acid Based Gemini Surfactant System

“…We previously found that the viscosity of the α-gel samples decreased as the shear rate increased (shear thinning) . This is a typical behavior in α-gel systems. ,,,,− We hypothesize that the shear thinning results from either the structural change (collapse) of the α-gel domains or the increased amount of excess water caused by shear flow. Therefore, we studied the α-gel bilayer structures under various shear rates (0, 0.001, 0.01, 0.1, 1, and 10 s –1 ) by the Rheo-SANS measurements.…”

A Sucrose Fatty Acid Ester-mixed Emulsifier as Stabilizer of Emulsion Systems

“…proven to be the typical features of layered gels 11) . Interestingly, the sample s critical shear stress (σ*) where the G equals to G present a unimodal distribution, with σ* of system S16Ca, S16Cb, S16Cd and S16Ce being about 67.60, 20.45, 31.28 and 39.79 Pa respectively.…”

“…Interestingly, the sample s critical shear stress (σ*) where the G equals to G present a unimodal distribution, with σ* of system S16Ca, S16Cb, S16Cd and S16Ce being about 67.60, 20.45, 31.28 and 39.79 Pa respectively. The reason behind this phenomenon is extremely complicated, but which could be considered as a new piece of rheological evidence to substantiate that S16Cb is indeed the criticality among whole systems 11) . These representations of amplitude sweep data were well consistent with the previous inference.…”

Control of Lipid Self-Assembled Structures & Assessment of Lipid Membrane Fluidity by Fluorescence Spectroscopy

“…This increase in the number of stratified vesicle structures was assumed to cause the decrease in viscosity. To the contrary, such stratified vesicle structures completely disappeared and, in their place, plate-like structures were observed in the system This study has reported for the first time that a certain silicone surfactant can also form an α-from hydrated crystal with higher alcohols 42 , and we designed and synthesized a novel silicone surfactant, 3-10-carboxydecyl-1,1,1,3,5,5,5-heptamethyl trisiloxane CDTS . CDTS was neutralized with triethanol amine TEA and the molar ratio of CDTS to TEA was 5:6.…”

“…All of these systems contain only hydrocarbon surfactants and there was previously no report indicating that silicone surfactants form α-form hydrated crystalline phases with higher alcohols. Recently, however, it has been reported that a certain type of silicone surfactant can form an α-form hydrated crystal with higher alcohols 42 .…”