关键词: 表面活性剂, 薄液膜, 去湿现象, 分离压, 数值模拟

Abstract:  Under slip boundary conditions, the dewetting of thin liquid films in the presence of insoluble surfactant monolayer was considered. Coupled nonlinear governing equations for the film thickness and surfactant concentration based on boundary layer theory were employed. The dewetting evolution of films was simulated using PDECOL program and the numerical results were presented, while the effects of characteristic parameters on dewetting process were discussed. The results show that the impact of Marangoni effect on the change rate of films thickness is not significant in vertical direction, the change rate of films thickness is dominated by disjoining pressure and capillary stress. The influence of Marangoni number M on static dewetted structures is not significant, and decreasing capillary number C will suppress the dewetting phenomenon effectively. Increasing slip coefficient β will accelerate the dewetting process and shorten the dewetted structures. Increasing equilibrium film thickness lc will lessen the deformation degree of surface and thereby lead the film thickness to be stabilized.  

Key words: insoluble surfactant, thin films, dewetting, disjoining pressure, numerical simulation