Prediction of the interaction potential of microgel particles from rheometric data. Comparison with different models

This work is concerned with the determination of the effective particle-par ticle interaction in colloidal suspensions from rheology. In particular, a concentrated microgel suspension is considered, in which particles interact through a repulsive polymer-polymer potential. The rheological modeling of this suspension was carried out by the authors in a recent;work. Here, the interaction potential provided by that model is compared with the ones res ulting from different models found in the literature. In this sense, a seri es of approaches relating the pair potential to rheological data such as dy namic modulus, viscosity, and yield stress is examined. Then the results of applying these models to experimental data are discussed, : showing the ad vantages and limitations of each approach for the particular case of concen trated microgel suspensions, de 'Gennes' theoretical pair potential for pol ymer-covered particles is also included for comparison. The proposed viscos ity model appears rather general and it is expected to have success in dete rmining the effective potential in colloidal systems with different particl e-particle force laws.