Phase behavior of phytanyl-chained akylglycoside/water systems

Abstract

The aqueous phase behavior of novel alkylglycosides, AGs, that have a 3,7,11,15-tetramethylhexadecyl (phytanyl) group as their hydrophobic part was examined as a function of the headgroup type, i.e., glycerol, xylose, glucose, and maltose in order of the increasing number of hydroxy groups of the headgroup. The aqueous phase structures at full hydration are well correlated with the headgroup size; an H _I I phase for the glycerol-headgroup, a cubic phase of crystallographic space group Pn3m / Pn3 at lower temperatures and an H _I I phase at higher temperatures for the xylose-headgroup, and an L_α phase for the glucose- and the maltose-headgroup. Krafft eutectic temperatures, T _K , of the phytanyl-chained AGs are significantly lower than those of conventional AGs, although the total number of carbon atoms in the hydrophobic group is as large as 20. Their low T _K values afford greater control of the aqueous phase structures at low temperatures.

Acknowledgements R.A.S. is grateful for the STA-fellowship. Financial support of AIST is highly acknowledged (Subject: Structures and functions of organized solutions). This work was also performed as a part of the International Joint Research Program 2001 supported by NEDO.