Abrahamsson Christoffer, Nordstierna Lars, Nordin Matias, Dvinskikh Sergey V, Nydén Magnus
Applied Surface Chemistry, Department of Chemical and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden; SuMo Biomaterials, VINN Excellence Centre, Chalmers University of Technology, 412 96 Gothenburg, Sweden.
Applied Surface Chemistry, Department of Chemical and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden.
J Colloid Interface Sci. 2015 Jan 1;437:205-210. doi: 10.1016/j.jcis.2014.09.031. Epub 2014 Sep 28.
The diffusion rate of water in dilute clay dispersions depends on particle concentration, size, shape, aggregation and water-particle interactions. As nontronite clay particles magnetically align parallel to the magnetic field, directional self-diffusion anisotropy can be created within such dispersion. Here we study water diffusion in exfoliated nontronite clay dispersions by diffusion NMR and time-dependant 1H-NMR-imaging profiles. The dispersion clay concentration was varied between 0.3 and 0.7 vol%. After magnetic alignment of the clay particles in these dispersions a maximum difference of 20% was measured between the parallel and perpendicular self-diffusion coefficients in the dispersion with 0.7 vol% clay. A method was developed to measure water diffusion within the dispersion in the absence of a magnetic field (random clay orientation) as this is not possible with standard diffusion NMR. However, no significant difference in self-diffusion coefficient between random and aligned dispersions could be observed.
水在稀黏土分散液中的扩散速率取决于颗粒浓度、大小、形状、聚集情况以及水与颗粒之间的相互作用。由于绿脱石黏土颗粒会沿磁场方向平行排列，因此在这种分散液中可产生定向自扩散各向异性。在此，我们通过扩散核磁共振和随时间变化的1H-核磁共振成像谱来研究片状绿脱石黏土分散液中的水扩散。分散液中黏土浓度在0.3%至0.7%（体积）之间变化。在这些分散液中的黏土颗粒经磁排列后，在黏土含量为0.7%（体积）的分散液中，平行和垂直自扩散系数之间测得的最大差值为20%。我们开发了一种方法来测量在无磁场（黏土随机取向）情况下分散液中的水扩散，因为使用标准扩散核磁共振无法做到这一点。然而，未观察到随机排列和经磁排列的分散液在自扩散系数上有显著差异。
