Effect of Freeze–Thaw Treatment on the Precipitation of Octyl <i>β</i>-D-Galactoside Hemihydrate Crystal from the Aqueous Solution

Abstract

Cryogenic treatment, like the freeze-thaw process, has been reported to be effective in modifying the physicochemical properties of polymeric hydrogels. However, not much attention has been paid to this process in terms of the precipitation of surfactant-water systems. In this study, two effective cryogenic methodologies were successfully reported to alter the physicochemical properties of a precipitate of an octyl β-D-galactoside (Oct-Gal)-water system. First, hyperrapid cooling (i.e., cooling at 30°C/min) was found to be an effective type of cryogenic treatment: the phase transition temperature (T) and enthalpy at the phase transition (∆H) between the crystal-dispersed phase and the sol (micelle) phase significantly decreased. In addition, cryogenic treatment in the presence of electrolytes, such as NaCl, NaBr, and CsCl, was effective even in the absence of the hyperrapid cooling condition. The hyperrapid cooling or the addition of certain electrolytes was considered to prevent the precipitation of the Oct-Gal hemihydrate crystals prior to the complete freezing of ice and the electrolyte/ice eutectic. Hence, the size of the aggregated crystals prepared by the above-mentioned effective cryogenic treatments seemed to be decreased compared with that of the normal precipitated crystals, thereby changing T and ∆H. Thus, two basic methodologies for the modification of the physicochemical properties of the crystal-dispersed phase of surfactant-water systems are discussed.

Aqueous Sugar-Based Amphiphile Systems: Recent Advances in Phase Behavior and Nanoarchitectonics

“…3) . Because the formation of nanofiber-based coagel is unique for C8Gal, consisting of galactose and normal octanol, the modification of the hydrogel by cryogenic treatment has been subsequently explored 47) . As a result, two effective cryogenic methodologies for changing the physicochemical properties of C8Gal Cr phases have been proposed.…”

n-Octyl (Thio)glycosides as Potential Cryoprotectants: Glass Transition Behaviour, Membrane Permeability, and Ice Recrystallization Inhibition Studies

“…The positive peaks at temperatures just below ice melting could be due to ice recrystallization, but may also be attributed to crystallization of synthesized glycosides, as recently shown by Ogawa and coworkers. [29] For the purpose of the present study, we are only interested in the glass transition properties, and so this was not pursued further.…”