Low Viscosity Reversed Hexagonal Mesophases Induced by Hydrophilic Additives.

Citation:

Idit Amar-Yuli, Wachtel, Ellen , Shalev, Deborah E, Aserin, Abraham , and Garti, Nissim. . 2008. “Low Viscosity Reversed Hexagonal Mesophases Induced By Hydrophilic Additives.”. Journal Of Physical Chemistry B, 112, 13, Pp. 3971–3982. doi:10.1021/jp711421k.

Abstract:

This study reports on the formation of a low viscosity HII mesophase at room temp. upon addn. of Transcutol (diethylene glycol mono Et ether) or ethanol to the ternary mixt. of GMO (glycerol monooleate)/TAG (tricaprylin)/water. The microstructure and bulk properties were characterized in comparison with those of the low viscosity HII mesophase formed in the ternary GMO/TAG/water mixt. at elevated temps. (35-40 °C). We characterized the role of Transcutol or ethanol as inducers of disorder and surfactant mobility. The techniques used were rheol., differential scanning calorimetry (DSC), wide- and small-angle X-ray scattering (WAXS and SAXS, resp.), NMR (self-diffusion and 2H NMR), and Fourier transform IR (FTIR) spectroscopies. The incorporation of either Transcutol or ethanol induced the formation of less ordered HII mesophases with smaller domain sizes and lattice parameters at room temp. (up to 30 °C), similar to those found for the GMO/TAG/water mixt. at more elevated temps. (35-40 °C). On the basis of our measurements, we suggest that Transcutol or ethanol causes dehydration of the GMO headgroups and enhances the mobility of the GMO chains. As a result, these two small mols., which compete for water with the GMO polar headgroups, may increase the curvature of the cylindrical micelles and also perhaps reduce their length. This results in the formation of fluid HII structures at room temp. (up to 30 °C). It is possible that these phases are a prelude to the HII-L2 transformation, which takes place above 35 °C. [on SciFinder(R)]
Last updated on 06/22/2020