Cooperative dynamics of didodecyldimethylammonium bromide / water / n-dodecane microemulsions: a dielectric relaxation study

TL;DRAbstract

A systematic study of the dielectric relaxation spectra of W/O (water-in-oil) microemulsions composed of didodecyldimethylammonium bromide (DDAB), water (W) and n-dodecane (D) has been made over the whole stability region in the phase diagram and over a wide range of frequencies (0.005 < nu/GHz < 89) at 25 °C. The spectra were best described by a superposition of six or five Debye processes, respectively, depending on the position of the sample in the phase diagram. Process 1 at 40 ns can be attributed to the transport of charge carriers between adjacent water droplets or along a percolation cluster. Processes 2 (at 8 ns) and 3 (at 1 ns, only detectable for large water droplets) can be ascribed to surface and radial counterion diffusion, respectively. Process 4 at approx. 200 ps is a reflection of uncorrelated movements of ionic species present in the microemulsion. Both processes 5 (at 12 ps) and 6 (at 3 ps) describe the cooperative relaxation of the H-bond network present in wa

Chat with Paper

AI Agents for this Paper