The report covers work from 2019 to 2023, initially focusing on broadening rheological responses in colloidal suspensions by altering the properties of their components. This aims to incorporate a wide range of behaviors into simple formulations, essentially achieving more with simpler mixtures. It highlights the significant impact of particle roughness on the shear thickening of stable suspensions and the more pronounced effects in colloidal gels. Rough particle gels demonstrate unique characteristics such as higher strain or stress thresholds for yielding, flow-independent porosity, and rapid recovery without thixotropy, attributed to hindered rolling motion of particles and clusters. Similar outcomes are achieved with anisotropic particles like rods, beneficial for preventing sedimentation.
The report then details advanced methods introduced for analyzing microscale rearrangements and correlating them to local forces. These include ultra-high-speed confocal rheometry, high-frequency rheology, orthogonal superposition rheometry, and AFMbased techniques. The application of these methods is demonstrated in simplified industrial systems, such as concentrated hydrogel dispersions (Carbopol) and paracetamol dispersions, offering valuable insights.
Lastly, it introduces a minimalistic model for pasty materials, combining a viscoelastic Maxwell model with stress-dependent relaxation time. This effectively describes the transition in pasty materials from elastic to plastic deformation, eliminating the need for a yield stress concept.