Speaker
Description
Brownian relaxation in colloidal suspensions has been observed in different susceptibilities such as shear moduli, viscosities or diffusion coefficients [1-6]. We present Brownian relaxation times obtained by Small Angle Oscillatory Shear (SAOS) measurements on suspensions consisting of two types of a low-molecular weight glass former (Diglycidyl Esther of Bisphenol A) filled with silica nanoparticles [7, 8]. In the description of the Brownian relaxation process, the radius of the colloidal particles is often chosen as a characteristic distance to describe the diffusion process. The related time, i.e. the time that colloidal particles in the suspensions need to travel this distance is then equal to the classical Peclet time. In the present contribution we will discuss the use of a concentration dependent characteristic length scale and examine the validity of this concept by comparing it to results from own measurements as well as to data reported in literature.
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