Freeze-fracture Transmission Electron Microscopy (FF/TEM) studies of systems containing self-associated structures

Abstract

Freeze-fracture transmission electron microscopy (FF/TEM) is a well-established and highly-valued technique, often employed in the study of biological systems which are extremely sensitive to structural alteration (e.g., membranes and tissues). The technique relies on rapid specimen cooling to immobilize detailed microstructure, usually in a hydrated environment, prior to fracture and subsequent surface replication. As Zasadzinski and Bailey point out, though, the principle governing this technique is general and can be applied with equal success to the study of “microstructured” or “complex” fluids, i.e., fluids consisting of self-organized supramolecular structures. In this vein, FF/TEM constitutes a powerful means of characterizing the structural attributes of dispersions, emulsions, gels, and liquid crystalline assemblies at relatively high spatial resolution. Such morphological information can prove valuable in the development of the structure-viscosity relationships needed in processing. Here, we demonstrate the utility of FF/TEM in elucidating the role of self-associated structures in three different systems: a chemical reaction environment, a high-internal-phase emulsion, and a nonaqueous gel.