The purpose of this investigation is to fabricate PDMS membranes with reliable surface roughness in order to reduce the surface resistances and to study its impact on the permeation rate. The permeance of CO₂ through PDMS membranes with rough surfaces at nanoscale is studied and compared with the one of membranes with flat surfaces. At very low thickness, rough membranes have a permeance greater than that of membranes with flat surfaces. The enhancement occurs in a regime where the gas transport is sorption desorption surface rate limited, and cannot be explained by the increase in surface area due to the corrugation. The analysis, introducing a phenomenological model in analogy with electrical flow, indicates that nano-corrugation reduces the surface resistance. To test the model, the permeance of N₂ is also measured in the same experimental conditions and the influence of surface roughness on permeation rate of CO₂, He, CH₄ and N₂ is studied. The comparison among the gases suggests that the Henry's coefficient depends on the surface roughness and allows discussing the role of roughness on membrane selectivity.

中文翻译：

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气体渗透通过橡胶状聚合物纳米波纹膜。

这项研究的目的是制造具有可靠表面粗糙度的PDMS膜，以降低表面电阻并研究其对渗透率的影响。研究了具有粗糙表面的PDMS膜在纳米级的CO ₂渗透率，并将其与具有平坦表面的膜的渗透率进行了比较。在非常低的厚度下，粗糙的膜的渗透率大于具有平坦表面的膜的渗透率。这种增强发生在气体传输受到吸附解吸表面速率限制的状态下，并且不能用波纹引起的表面积增加来解释。该分析引入了类似于电流的现象学模型，表明纳米波纹降低了表面电阻。要测试模型，N的磁导率₂是在相同的实验条件和表面粗糙度对CO的渗透速率的影响也测量₂，他，CH ₄和N ₂进行了研究。气体之间的比较表明，亨利系数取决于表面粗糙度，并允许讨论粗糙度对膜选择性的作用。