Role of solvent identity in impact-activated solidification of dense suspensions

Applied stress can drive flowing suspensions of solid particles in a Newtonian liquid into a shear-jammed solid state. Beyond steady state rheology, recent work demonstrated that high-speed ultrasound imaging could be used to visualize transient flow fields generated by impact and track the propagation of “jamming fronts” in optically opaque cornstarch suspensions [1][2]. We here use this ultrasound imaging technique to reconstruct the flow fields caused by impact of dense suspensions containing silica nanoparticles in polymeric liquids. We find that the solvent molecular weight plays an important role in mediating frictional contacts between particles required for shear jamming.
[1] E. Han, I. R. Peters and H. M. Jaeger. High-speed ultrasound imaging in dense suspensions reveals impact-activated solidification due to dynamic shear jamming. Nat Commun, 7:12243, 2016.
[2] E. Han, L. Zhao, N. Van Ha, S. T. Hsieh, D. B. Szyld. and H. M. Jaeger. Dynamic jamming of dense suspensions under tilted impact. Phys. Rev. Fluids 4, 063304, June 2019.