Modelling of the aggregation process using the citrate synthesis of gold as case study

This work presents modelling for the aggregation process of metal nanoparticles following a theory proposed in literature. In this theory, metal atoms aggregate into particles of bigger size due to Van der Waal's forces of attraction. Then, owing to the electrostatic forces of repulsion, the particles eventually stop aggregating and become stabilized. Based on this mechanistic description, we developed a model for the aggregation process. Because this process often occurs along with other processes, such as growth, we employed as case study the synthesis of gold nanoparticles by the citrate synthesis method for conditions where the aggregation process is decoupled from the growth process. Using this model, we calculated the seed particle sizes and compared them with the values previously reported in literature. Furthermore, we calculated the final particle sizes and compared them with experimental data. The results show excellent agreement.