Light scattering investigation of electric field alignment of phospholipid tubules

The polymerizable diacetylenic phospholipid 1,2-bis(10,12,tricosadiynoyl)-sn-glycero-3-phosphocholine (DC(23)PC) forms straight hollow cylinders in water. Using an ac electric field it was possible to achieve significant orientational alignment of the tubules parallel to the field direction, and from light scattering results deduce an effective dielectric susceptibility anisotropy Deltachi(E). Moreover, we suggest that the alignment arises from an orientational anisotropy of the total electrostatic enthalpy for a dielectric tubule in an electric field, rather than an inherent polarizability anisotropy of the constituent DC(23)PC molecules, as was the case with magnetic field alignment.