Dependence on oil chain-length of the curvature elastic properties of nonionic surfactant films: Droplet growth from spheres to a bicontinuous network

Using NMR self-diffusion and H-2-NMR relaxation experiments, we have investigated growth of oil-in-water microemulsion droplets when spontaneous curvature is lowered, starting at emulsification failure boundary. We compare two ternary nonionic microemulsion systems, containing penta-ethylene glycol dodecyl ether (C12E5), and decane or hexadecane, at same surfactant-to-oil ratio and approximately the same spontaneous curvature. Droplet growth in microemulsions appears in general to be only minor. Quantitative differences between the two systems indicate differences in the curvature elastic constants