Diffusive Wave Spectroscopy (DWS) is an optical technique to perform rheological measurements by means of following the motion of a dispersed phase in the limit of multiple scattering. The basic assumption of microrheology is that the motion of the dispersed phase is determined by the mechanical properties of the continuous medium. As the equipment can resolve extremely fast displacements of colloids, we have access to data at really high frequencies, setting this technique apart from traditional rheology.
DWS can be used to characterize turbid colloidal dispersions, e.g. determining droplet size or the ageing of emulsions or to perform rheological measurements on polymer gels or worm-like micelles. Experimental temperatures can be controlled from 10 oC up to 60 oC, allowing the study of gelation processes, for instance.