依据荷叶表面具有的不规则自相似微纳双重结构,引入分形几何学构造类似荷叶的随机分形结构,建立相应的Cassie、Wenzel模型接触角方程,分析随机分形结构的分形维数和结构参数对其润湿性的影响.结果表明:分形结构表面的分形维数越大,结构越致密,接触角越大；分形结构中微/纳尺度参数之比越大,接触角也越大.然而,随机结构即使分形维数趋于最大的3.0,Wenzel模型表观接触角也不能达到超疏水的150°,Cassie模型最大表现接触角大于150°；更适合用于制备超疏水表面.%On the basis of lotus leaf surface with irregular self-similar microano dual structure, fractal geometry was used to construct random fractal structure similar to the lotus leaf. The corresponding contact angle equations with Cassie, Wenzel model were established, and the effects of fractal dimension and structural parameters on wettability of the random fractal structure were analyzed. The results show that the structure becomes compacter and the contact angle becomes bigger with the increasing of fractal dimension for the surface fractal structure, and the contact angle becomes greater with the larger ratio of microano scale parameter. However, the apparent contact angle of Wenzel model can not reach 150° with super hydrophobic even if the fractal dimension is tend to the maximum 3. 0. The maximum apparent contact angle of Cassie model is larger than 150°. So Cassie model is more suitable for super-hydrophobic surface.
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