We have studied the topological transition of the nonionic micelles of a penta-ethyleneglycol mono $n$-dodecyl ether $({\mathrm{C}}_{12}{E}_5)/\mathrm{D}\mathrm{L}\mathrm{\text{−}}\alpha$-phosphatidylcholine Dimyristoyl (DMPC) mixture in water by light scattering and viscosity measurements. The topological transition concentration decreases with an increase of the mixing ratio of DMPC to ${\mathrm{C}}_{12}{E}_5$. The topological transition point is strongly affected by defect energies of the end cap (${ϵ}_1$) and a threefold junction (${ϵ}_3$) and is compared with a recent theoretical study. This experimental study shows the first clear evidence for the topological transition in a nonionic micellar system resulting from balancing the defect energies.

• Received 16 May 2002

DOI:https://doi.org/10.1103/PhysRevLett.89.258302