Synthesis and self-assembly of polymer-grafted nanoparticle thin-films

The formation of ordered and disordered structures in materials can strongly influence their macroscopic behavior. Hyperuniform structures, which are characterized by the suppression of density fluctuations at large length scales, have recently been recognized for their potential to exhibit photonic or phononic band gaps in a locally disordered material. In polymer-grafted nanoparticle (PGN) composites, this structure and order arises from many different processing parameters and plays a critical role at multiple length scales, from particle-polymer interfaces to particle morphology to large-scale particle arrangements. Understanding and controlling the structure at these scales is key to understanding the measured macroscopic properties. The self-assembly of PGN thin films can be influenced by factors such as polydispersity, composition, and film deposition method. Here, we tailor the synthesis and assembly of thin films from bidisperse size distributions of spherical polymer-grafted nanoparticles, relying on drop casting and flow-coating processes for their ease of implementation and scalability. By varying the solution concentration, flow-coating parameters, and particle size distribution, we can control large-scale self-assembly of the particle microstructure, which we characterize via electron microscopy and light scattering to assess the degree of hyperuniformity and orientational disorder. This multiscale process-structure-property understanding will influence the design of materials for a variety of applications and environments.