Shear banding in drying colloidal films studied using scanning micro small angle x-ray scattering*

Shear banding is an important phenomenon observed in a range of fields in materials science, such as bulk metallic glasses, granular, complex fluids. A particularly challenging task is to relate the changes in material microstructure to the observed shear banding. In this study we exploit the capabilities of the scanning micro small angle x-ray scattering technique at the European Synchrotron and Radiation Facitility (ID13) to explore how the maximum strain magnitude and direction, and the local film density vary spatially around shear bands formed in a drying colloidal film. We also show how reducing the film growth rate can lead to crystalline microstructure which appears to suppress shear band formation.In these samples, the scanning micro-SAXS technique is used to follow changes that occur as a colloidal film forms and undergoes compaction in real time.