Description of ionic surfactant/water system by adjusting mesoscopic parameters.

Dissipative particle dynamics simulations were utilized to simulate a model surfactant solution-air system. Amphiphilic surfactant molecules were modeled as dimers composed of a hydrophilic head and a hydrophobic tail. With a simple model, the influence of conservative interaction parameters on the surfactant's properties, including surfactant efficiency and critical micelle concentration (CMC), was investigated in the present research. It is not the surfactant total concentration, but the bulk concentration, that should be employed to achieve the right surfactant properties. It is found that the adjustment of interaction between water and head or air and tail (a(WH) or a(AT)) will result in the obvious change in surfactant efficiency. The parameter that affects CMC the most significantly is the interaction between water and tail (a(WT)). On the basis of the findings about the relationship between conservative interaction parameters and surfactant behaviors, we varied the interaction parameters and simulated a real ionic surfactant system with different tail lengths.