Figure 3.

Epifluorescence micrographs of a lipid monolayer consisting of DMPS, DMPC, and DChol in the absence and presence of an inhomogeneous electric field. The monolayer contains 21.6 mol% DMPC, 43.2 mol% DMPS, 35 mol% DChol, and 0.2 mol% TR-DHPE. In a, the surface pressure is 21 mN/m, well above the critical pressures for the system (see Fig. 1a), and there is no electric field. The monolayer appears uniformly gray around the electrode. In b, a positive potential of 150 volts has been applied, and domain formation can be seen in a narrow band around the electrode.