Lipid-similar thermal transition of polyethylene glycol alkyl ether detergents

A narrow, reversible endothermic main transition is found in the aqueous micellar phase of octaethylene glycol tetradecyl ether (C14E8) by DSC, characterized by a transition temperature of 41 degrees C and a Delta H value of 0.5 kcal mol(-1), which is not observed by light scattering. This transition is assigned to a cooperative conformational rearrangement of the assembled amphiphilic detergent molecules and not to a micelle aggregation process. It is suggested that the detergent's polar head group is primarily involved in this rearrangement.