Determination of suspension redispersion quality with static multiple light scattering

 
A technique based on Static Multiple Light Scattering is proposed to characterize dispersions all along their formulation process from dispersibility to redispersion passing by physical stability. The formulation of suspensions considers the conditions to prepare an homogeneous suspension and keeping it stable as long as possible. Depending on the application, the suspension can settle and need to be redispersed before use. The formulation department needs to control the redispersion process to advice consumer the conditions to apply to reach good dispersibility level. The technique presented here has the advantage to measure the suspension in a large range of concentration between 0.0001 and 95%, for sizes between 10 nm and 100 µm without sample dilution. In this work we present different studies showing how the technique is useful in the different steps of the formulation like dispersibility characterization of pigment, mean size measurement, suspension characterization after redispersion under different stress.