Facile sample preparation method allowing TEM characterization of the stacking structures and interlayer spaces of clay minerals

• Published in: Applied clay science 2019-04, Vol.171, p.1-5
• Main Authors: Liu, Dong, Tian, Qian, Yuan, Peng, Du, Peixin, Zhou, Junming, Li, Yun, Bu, Hongling, Zhou, Jieyu
• Format: Article
• Language: English
• Subjects: Clay minerals; Interlayer organic matter; Sample preparation; Stacking structure; TEM
• ISSN: 0169-1317; 1872-9053
• DOI: 10.1016/j.clay.2019.01.019

Transmission electron microscopy (TEM) is an essential and irreplaceable technique for studying the micromorphology and microstructure of clay minerals. However, observing layer stacking and detecting the interlayer spaces of clay minerals by TEM are still major challenges, due to the difficulty of finding suitable fields of view for clay planes along the [00l] direction. A simple and effective sample pretreatment method was proposed here for TEM characterization of clay mineral stacking structures and interlayer spaces. Using this method, clay mineral-bearing ultrathin slices, in which clay minerals particles showed an orientated arrangement, were prepared based on the resin embedding method. The (00l) plane of clay minerals was exposed toward electron beams during TEM analysis, and fields of view along the [00l] direction were observed, accordingly. This method is thus particularly useful for the observation of stacking information and detection of interlayer regions in clay minerals. The validity of this method is exemplified by its application to pure kaolinite and clay mineral-rich shale samples which contains several clay minerals and the clay mineral-organic matter complexes. •A novel sample preparation method for TEM observation of clay mineral is proposed.•The method is based on the unique property of preferred orientation of clay minerals.•Observing layer stacking structures of clay mineral is easy using this method.•Interlayer organic matter in clay minerals was detected by TEM using this method.