The assembly of nanoparticles (NPs) into colloidal crystals is a promising way to obtain ordered nanocomposite materials with unique properties determined by the choice of the constituent NPs. If successful, this novel approach will have a significant impact on the ability of experimentalists to rationally design ordered colloidal crystals for a wide range of optical and catalytic applications, such as photonic crystals, optical switches and filters, and catalytic devices. The PIs have shown a novel way to selectively stabilize one crystal structure over another possible one by the use of polymers that can intercalate between the NPS.
The PIs have made an interesting discovery that, even when the energy, pressure, and packing fraction for two crystal isomorphs, e.g., HCP and FCC, are the same, the distribution of voids within the crystals are different. By filling the voids with polymers of different length, they were able to show that one can selectively stabilize HCP over FCC crystals. Based on these findings, they propose to make use of this novel insight about void symmetries and size-distributions to select a desired polymorph from a suite of competing crystal structure. In this proposal, they will use molecular dynamics (using Graphics Processing Unit (GPU)-based molecular dynamics simulations) and Monte-Carlo methods to study the colloidal crystals in colloid/polymer blends, . They will explore several structures of spherically symmetric and patchy particles with polymers of varying conformation and flexibility in order to understand how to maximize the polymers' entropy in voids of different geometries, and how the introduction of enthalpic interactions may act in counterbalance to the polymer entropy.
