Gas barrier in polymers is able to be effectively enhanced by adding air-impervious nano-fillers. It is inevitable that there are some defects or caves on the surface of nano-fillers, which can have a certain effect on the gas barrier. The effect of defects and caves in nano-fillers was investigated using the finite element model in order to better understand the diffusion process in a polymer nanocomposite film with staggered array nano-fillers by varying the microstructural features such as volume fraction, aspect ratio, gaps between fillers, and so on. The results showed that the effect of defects and caves on relative diffusivity arises from the following two aspects: the first is the effect of cave volume which dominates, and the second is the induced effect from defects and caves. A theoretical model for predicting relative diffusivity was developed based on the volume effect, and then was generalized into three dimensions. In order to estimate the value range of the model, the upper and lower boundaries of the model have been derived. Comparisons were then made between the estimated and simulated values, and the results showed that the upper and lower boundaries are basically correct, and especially the upper boundary is on the same order of magnitude as the real value.

通过添加不透气的纳米填料，能够有效增强聚合物的气体阻隔性。纳米填料表面难免存在一些缺陷或空穴，会对气体阻隔产生一定的影响。为了通过改变体积分数、纵横比、间隙等微观结构特征，更好地了解具有交错阵列纳米填料的聚合物纳米复合膜中的扩散过程，使用有限元模型研究了纳米填料中的缺陷和洞穴的影响填料之间，等等。结果表明，缺陷和溶洞对相对扩散率的影响主要来自以下两个方面：一是溶洞体积的影响占主导地位，其二是缺陷和溶洞的诱发作用。基于体积效应建立了预测相对扩散率的理论模型，然后将其推广到三个维度。为了估计模型的取值范围，推导了模型的上下边界。然后将估计值和模拟值进行比较，结果表明上下边界基本正确，尤其是上边界与真实值处于同一数量级。