Link between permanent shear-banding and local concentration fluctuations in suspensions of compressible microgels

We uncover the occurrence of shear banding in dense suspensions of compressible microgels. Velocimetry measurements evidence the presence of permanent but unsteady shear-banding for sufficiently small Peclet numbers, with the formation of a central plug-like flow. Small-angle neutron scattering experiments under shear link the observed banding phenomenon to structural variations along the velocity gradient, providing a connection between the arrested band and the increase in structural correlations associated with changes in the local packing fraction. This provides unique evidence of a shear–concentration coupling mechanism in jammed suspensions of compressible particles.