Role of the polydispersity of nanoparticle size, grafted chain length and grafting density on the self-assembly of polymer nanocomposites

The self-assembly of polymer chain-grafted-nanoparticles in polymer matrix leads to the formation of different superstructures, e.g., well-dispersed particles, strings, and aggregates. However the effect of polydispersity of individual parameters, e.g., particle size, grafting density and chain length is not comprehensively understood. We show that these distributions lead to a variety of superstructures being formed in the sample, and that the polydispersity of superstructures formed in the same polymer matrix is governed by the inherent polydispersity of nanoparticle size and grafting density. Further, it is found that increasing the polydispersity of the length of the grafted chains leads to less aggregated structure based on a simple geometric parameter of particle to polymer size ratio. Thus, we conclude that the distribution of nanoparticle sizes is the most important variable in this context.