Abstract The structure of halloysite nanotubes (Hal) from different mines was investigated by Small-Angle Neutron Scattering (SANS) and Electric Birefringence (EBR) experiments. The analysis of the SANS curves allowed us to correlate the sizes and polydispersity and the specific surfaces (obtained by a Porod analysis of the SANS data) of the nanotubes with their specific geological setting. Contrast matching measurements were performed on patch Hal (from Western Australia) in order to determine their experimental scattering length density for a more precise analysis. Further characterization of the mesoscopic structure of Hal was carried out by Electric Birefringence (EBR), which allowed to study the rotational mobility of Hal. From the obtained rotational diffusion coefficients of the different Hal we deduced their length via the Broersma theory, which compares well to TEM data. The analysis of both SANS and EBR data provided a bulk average information on the Hal structure in water, which, for instance, documented the markedly higher degree of well-definedness of the PT-Hal and the thinner tube walls present here. The attained systematic structural knowledge represents a step forward for the robust structural description of halloysites selected from four geological deposits and shows that Hal of different origin differ very markedly with respect to their mesoscopic structure.

中文翻译：

---

通过小角中子散射 (SANS) 和电双折射对不同来源的埃洛石纳米管进行结构比较

摘要 通过小角中子散射（SANS）和电双折射（EBR）实验研究了不同矿山埃洛石纳米管（Hal）的结构。SANS 曲线的分析使我们能够将纳米管的尺寸和多分散性以及特定表面（通过 SANS 数据的 Porod 分析获得）与其特定地质环境相关联。对补丁 Hal（来自西澳大利亚）进行对比匹配测量，以确定它们的实验散射长度密度，以便进行更精确的分析。Hal 的介观结构的进一步表征是通过电双折射 (EBR) 进行的，它允许研究 Hal 的旋转迁移率。根据获得的不同 Hal 的旋转扩散系数，我们通过 Broersma 理论推导出它们的长度，这与 TEM 数据比较好。SANS 和 EBR 数据的分析提供了水中 Hal 结构的整体平均信息，例如，它记录了 PT-Hal 的明显更高程度的明确定义和此处存在的更薄的管壁。获得的系统结构知识代表了从四个地质矿床中选出的埃洛石的稳健结构描述向前迈进了一步，并表明不同来源的 Hal 在其细观结构方面存在显着差异。