“Chloritized” vermiculite coexisting with kaolin-group minerals, vermiculite, mica, and gibbsite in the 0.2–0.5-µM fraction separated from a Korean Ultisol was studied by ultramicrotomy and high-resolution electron microscopy. The (001) lattice images observed from thin sections showed that the “chloritized” vermiculite was composed of particles which differed in their shape and the stacking of silicate layers. On saturation with K+, the silicate layers had spacings of 14–10 Å, with 14–12-Å layers being dominant. The 8–7-Å layers of a few particles appeared to be segregated close to the basal plane surfaces, but not necessarily close to the edge surfaces. The silicate layers were more or less curved and wavy and were commonly discontinuous. They formed packets (100–500 Å thick) by stacking, which were associated “face-to-face” and/or “edge-to-edge” or stacked parallel or subparallel to form particles of different shapes. The extent of interlayer collapse of the 14-Å layers on heating differed from one particle to the other, but was fairly uniform within a particle. Treatment with hot 1/3 M sodium citrate dissolved the interlayer material and possibly the material present between the packets from the “chloritized” vermiculite and from a few fine plates of kaolin-group minerals. The interlayer material and its chemical composition, therefore, could not be determined.

Understanding the physical structure of greases can provide critical insight into improving the lubricating performance of a grease. Observation of the grease structure can be quite difficult depending on the type of grease and the length scale of the structure. Polyurea greases in previous reports have typically been examined by removal of the oil phase, which significantly changes the polyurea structure. This paper examines the effect of sample preparation conditions on the microstructure of polyurea greases. This study reveals new structures in the polyurea that have not been observed in the previous literature, including entangled fibers and nanotubes. Correlation is found between the observed polyurea microstructure coverage and grease stiffness.

A new transmission electron microscopy (TEM) specimen preparation method that utilizes a combination of focused ion beam (FIB) methods and ultramicrotomy is demonstrated. This combined method retains the benefit of site-specific sampling by FIB but eliminates ion beam-induced damage except at specimen edges and allows recovery of many consecutive sections. It is best applied to porous and/or fine-grained materials that are amenable to ultramicrotomy but are located in bulk samples that are not. The method is ideal for unique samples from which every specimen is precious, and we demonstrate its utility on fine-grained material from the one-of-a-kind Paris meteorite. Compared with a specimen prepared by conventional FIB methods, the final sections are uniformly thin and free from re-deposition and curtaining artifacts common in FIB specimens prepared from porous, heterogeneous samples.

Ionic liquids (ILs) and their mixtures with low molecular solvents present ideal properties for use as flotation liquids in cryo-ultramicrotomy. With control of Tg and η by co-solvent addition, flat, ultra-thin sections are reliably floated onto transmission electron microscopy grids even at temperatures as low as −100°C. Even more, the liquids and their mixtures are stable in the microtome trough for several hours because of low vapor pressure and low solidification temperature. Compared to established flotation media for soft polymer systems, the time and skill needed for cryo-ultramicrotomy are significantly reduced. Although just a handful of ILs are discussed and a good general choice identified, if different liquid characteristics are needed for a particular sample, thousands of additional ILs will perform similarly, giving this new approach enormous flexibility.

Ultramicrotomy, the technique of cutting nanometers-thin slices of material using a diamond knife, was applied to prepare transmission electron microscope (TEM) specimens of nanoporous poly(methylsilsesquioxane) (PMSSQ) thin films. This technique was compared to focused ion beam (FIB) cross-section preparation to address possible artifacts resulting from deformation of nanoporous microstructure during the sample preparation. It was found that ultramicrotomy is a successful TEM specimen preparation method for nanoporous PMSSQ thin films when combined with low-energy ion milling as a final step. A thick, sacrificial carbon coating was identified as a method of reducing defects from the FIB process which included film shrinkage and pore deformation.