Passive Microrheology for Measurement of the Concentrated Dispersions Stability

This work presents a new technique of passive microrheology for the study of the microstructural properties of soft materials such as emulsions or suspensions. This technology uses Multi Speckle Diffusing Wave Spectroscopy (MS-DWS) set-up in a backscattering configuration with video camera detection. It measures the mean displacement of the microstructure particles in a spatial range between 0.1 and 100 nm and a time scale between 10−2 and 105 s. Different parameters can be measured or obtained directly from the Mean Square Displacement (MSD) curve, including a fluidity index, a solid–liquid balance, an elasticity index, a viscosity index, a relaxation time and a MSD slope.