Interparticle attraction controls flow heterogeneity in calcite gels

We couple rheometry and ultrasonic velocimetry to study experimentally the flow behavior of gels of colloidal calcite particles dispersed in water, while tuning the strength of the interparticle attraction through physico-chemistry. We unveil, for the first time in a colloidal gel, a direct connection between attractive interactions and the occurrence of shear bands, as well as stress fluctuations. This generalizes previous results on dense, jammed systems like emulsions [Becu et al., Phys. Rev. Lett., 2006, 96, 138302, Ragouilliaux et al., Phys. Rev. E, 2007,76, 051408].