Equilibrium, dynamic and simulation studies of AOT reverse micellar, carbon black and fullerene colloidal systems.

摘要

Equilibrium and dynamic studies were performed on the association colloidal system AOT/water in the nonpolar solvent CCl{dollar}sb4{dollar} to study the effect of solubilized water on the size, shape and interaction properties of the reverse micelles. The hydrodynamic diameters determined by viscosity and dynamic light scattering were found in good agreement with each other and with other experimental data. Electric field-induced birefringence measurements showed negative birefringence. The measured and calculated relaxation times indicated the presence of inter-micellar interactions.; Atomic level molecular simulations with the ESFF forcefield were used to identify the most stable geometries of the AOT molecule in vacuum, water and CCl{dollar}sb4.{dollar} In this approximation, the energies of interaction between AOT and individual water molecules were determined. Calculated geometrical parameters of the AOT molecule were applied toward the estimation of the size and aggregation number of reverse micelles, and were found in good agreement with experiments.; The dispersion colloid systems N660 and N299 carbon black suspensions and fullerene aggregates were studied by performing viscosity as well as dynamic and static light scattering measurements. Stability properties, size distribution and deviation from the spherical shape were analyzed. Close to equilibrium, dynamic measurements indicated positive birefringence for all three systems. Perturbation by high-energy laser pulses resulted in non-linear behavior for the carbon black samples. A characteristic signature peak of C{dollar}sb{lcub}60{rcub}{dollar} was identified in the UV-vis spectrum of N660.