“Properties matter, not the molecules.” – E.L. Cussler.
Our paper on droplet impact with yield-stress fluids on coated substrates is now online:
Sen, S., A. G. Morales, and R. H. Ewoldt, “Viscoplastic drop impact on thin films,” Journal of Fluid Mechanics, 891, A27 (2020). DOI link
We have demonstrated that, as long as the macroscopic rheological flow properties are the same, the microstructural route to those properties itself does not matter. This experimental work demonstrates the generality of a simple dimensionless scaling idea based on forces during drop impact, and its material agnosticity across two vastly different viscoplastic fluids: Laponite clay and Carbopol microgel.
The supplementary video to the paper, showing the various types of impact behaviors observed in the study.