抄録
The microscopic investigation of the dynamics of surfactant molecules near the air/water interface is essential for the overall understanding of adsorption phenomena and the construction of a practical adsorption model. In this paper, by molecular dynamics method, we have simulated the adsorption of ethanol molecules from bulk water solution to pure interface. The calculated density profile along the axis vertical to the interface showed three distinct region; i. e. the adsorbed interface, the bulk solution, and the intermediate diffusion area. Counting the number of ethanol molecules included in the first region, we estimated the surface excess amount of ethanol at each time. In addition, using the autocorrelation function method, we estimated the adsorption flux and desorption flux at every 50ps. As a result we confirmed that the desorption flux monotomically increased with the surface excess increasing and accordingly balanced with adsorption flux at adsorption equilibrium state, while the adsorption flux varied in rather complicated style. We also finded the noticeable chage of the desorption collision dynamics just before the adsorption equiriblium establishment.
