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 pro cess. In particular, the aggregates' fractal dimension was determined by st atic light scattering. The results indicate that the aggregates are more co mpact than expected for diffusive aggregation. A reversible aggregation mec hanism is proposed on the basis of the competition between osmotic and elas tic contributions arising from the soft character of the particles. Aggrega tion proceeds in an energy minimum of restricted depth, giving rise to the formation of more compact dusters than expected. Finally, the process rever sibility is tested, confirming the secondary minimum controlled aggregation .