Reversible aggregation of soft particles

In this work, the aggregation of microgel particles has been investigated, paying special attention to the structure of the clusters formed in the process. In particular, the aggregates' fractal dimension was determined by static light scattering. The results indicate that the aggregates are more compact than expected for diffusive aggregation. A reversible aggregation mechanism is proposed on the basis of the competition between osmotic and elastic contributions arising from the soft character of the particles. Aggregation proceeds in an energy minimum of restricted depth, giving rise to the formation of more compact dusters than expected. Finally, the process reversibility is tested, confirming the secondary minimum controlled aggregation.