When considering porous materials that are shaped under a specific form for a given application, a possible anisotropy of structure, that could be created by the synthesis procedure, have to be considered. This anisotropy may have consequences on the transport properties. To evidence such anisotropy, several methods are proposed here in the case of extrudates of alumina used as catalysts supports. The simplest one seems to be the release of probes, here a salt, in controlled geometry. Electrical measurements are also simple in principle but limited to aqueous solutions and to pore size ranges where the double layer can be screened. NMR is a very powerful tool, but the porous domain that is analyzed is often questionable. Finally, approaches such as band spreading analysis of chromatographic peak are also interesting in their ability to explore various pore domains by changing probe size, but a modeling is needed and the preparation of adapted columns is sometimes itself a difficult task. The tortuosity of the material, analyzed here in longitudinal and transverse directions, is used as an intercomparing parameter.

当考虑为给定应用以特定形式成形的多孔材料时，必须考虑可能由合成程序产生的结构各向异性。这种各向异性可能会对传输性能产生影响。为了证明这种各向异性，在将氧化铝挤出物用作催化剂载体的情况下，本文提出了几种方法。最简单的方法似乎是按受控的几何形状释放探针（此处为盐）。电气测量原则上也很简单，但仅限于水溶液和可筛选双层的孔径范围。NMR是一种非常强大的工具，但是所分析的多孔区域通常令人怀疑。最后，诸如色谱峰的谱带扩展分析之类的方法也很有趣，因为它们能够通过改变探针大小来探索各种孔结构域，但是这需要建模，而制备适合的色谱柱本身有时也是一项艰巨的任务。在这里，在纵向和横向上分析的材料的曲折度用作比较参数。