关键词: 浸润, Ising模型, Monte Carlo方法

Abstract: A statistical model,the two-dimensional Ising model,combined with Monte Carlo method,is applied to analyze quantitatively the wetting behavior of liquid in fibrous assemblies,which is regarded as the space between fibers changed from gas dominant state to liquid dominant state. Such change is driven by the difference in energy between the two states and finally terminated by the balance of surface tension and gravity. To accommodate the Ising model to the process of liquid wetting in fibrous assemblies,new sets of variables,si=1(liquid cell) or 0(gas cell),Fi=1(fiber cell) or 0(cell without fiber),are adopted to study the wetting dynamics. Characteristics of interacting fiber materials and liquid can be represented in the coefficients of the adhesive energy between fiber and liquid and cohesive energy within liquid. Work of extrinsic force,the surface tension,has been taken into account for its contribution to the energy of the system derived from liquid and the fibrous assemblies. Results of simulation are in good agreements with wicking experiments,indicating good prospect of the method to be used in this area. The model can be modified to adapt to wetting process of liquid on more complex pattern of structures by altering the initial configuration of fiber assemblies. For example,it is used to simulate the wetting process in an isotropic fiber network and the wetting process in a filament bundle. The results are showed in Fig.2～3.

Key words: Wetting, Ising model, Monte Carlo method