Cryo-scanning electron microscopy (cryo-SEM) has become a powerful tool for characterizing complex fluids, bridging microscopic structure and macroscopic rheology. In this work, we provide practical guidelines for optimizing for the application of cryo-microscopy, emphasizing the importance of tailoring experimental parameters to the specific chemical and physical properties of the fluid. Key considerations include freezing methods, fracturing precision, controlled sublimation, and optimized coating thickness. Using Carbopol, xanthan gum, and Laponite as model fluids, we demonstrate that the observed microstructures reflect intrinsic properties rather than artifacts of sample preparation. However, inadequate freezing or over-sublimation, as well as improper handling such as rapid sublimation, air bubble entrapment, or excessive coating, can compromise the results, whereas optimized conditions effectively preserve the native network structures. The microstructural changes revealed by cryo-SEM correlated directly with rheological properties, such as yield stress increase with Carbopol concentration and reversible thixotropic recovery in Laponite. We highlight both the potential and the limitations of cryo-SEM, underscoring its role as a complementary methodology to rheological analysis in soft matter research and industrial applications.
Castaño et al. (Thu,) studied this question.