Department of Chemical Engineering, KU Leuven, W. de Croylaan 46, B-3001, Heverlee, Belgium.
Langmuir. 2013 Aug 13;29(32):10059-65. doi: 10.1021/la401897n. Epub 2013 Jul 29.
We report a first application of vertical small-angle X-ray scattering to investigate the drying process of a colloidal suspension by overcoming gravity related restrictions. From the observation of the drying behavior of charge-stabilized colloidal silica in situ, we find the solidification of the colloidal particles exhibits an initial ordering, followed by a sudden aggregation when they overcome an electrostatic energy barrier. The aggregation can be driven not only by capillary pressure but also by thermal motion of the particles. The dominating contribution is determined by the magnitude of the energy barrier at the transition, which significantly decreases during drying due to an increased ionic strength.
我们首次应用垂直小角 X 射线散射来研究胶体悬浮液的干燥过程，克服了与重力相关的限制。通过原位观察带电稳定胶体二氧化硅的干燥行为，我们发现胶体颗粒的凝固表现出初始有序性，随后在克服静电能垒时突然聚集。这种聚集不仅可以由毛细压力驱动，还可以由颗粒的热运动驱动。主导贡献取决于转变过程中能垒的大小，由于离子强度的增加，该能垒在干燥过程中显著降低。
