Analysis of Powder Caking in Multicomponent Powders Using Atomic Force Microscopy to Examine Particle Properties

Atomic force microscopy has been used to study the surface properties of model spray dried powders. Phase imaging, nanoindentation and force modulation microscopy have differentiated between the different surface material properties of the particles, revealing a regular dispersion of soft, oil rich areas distributed across the particles' surface. Humidity and temperature cycling effects on the caking behavior of the particles have also been investigated, with significant morphology changes and onset of caking found to occur within relatively short periods of time. Understanding the caking behavior of powders can be difficult when bulk powder properties are studied due to the many factors affecting caking and the complex interactions between individual particles. This work demonstrates the advantages and the additional information that using atomic force microscopy can bring to studying the properties of powdered materials and how the data can be used in relation to powder caking.