SANS and dynamic light scattering to investigate the viscosity of toluene under high pressure up to 1800 bar

We present a joint experimental study of small angle neutron scattering (SANS) and dynamic light scattering (DLS) under high pressures up to 1800 bar on a colloidal suspension, which consists of a core–shell system made of sterically stabilized silica particles grafted with octadecyl chains in toluene. From the analysis of SANS contrast variation under pressure, we could estimate the amount of compression in both core and shell under the action of pressure. The DLS measurements under pressure yield a diffusion coefficient which enabled us together with the SANS result to evaluate the pressure-dependent viscosity of the dilute suspension which is to a good approximation the solvent viscosity on the basis of the Stokes–Einstein relation. The excellent comparison of the so-calculated pressure-dependent viscosities of toluene with literature values demonstrates the value of our method to measure viscosities under pressure.