Precise, large-scale assembly of polymer-grafted nanoparticles (PGNs) has shown great promise for the scalable manufacturing of sensors, energy storage devices, and photonic elements. Different than more traditional ligand-coated nanoparticles, PGNs are stabilized by high molecular weight polymers at relatively low grafting densities. In this regard, PGNs behave as soft colloids, exhibiting characteristics of both a hard sphere and a soft polymer depending on the architecture of the polymer canopy and deformation rate. Our previous reports demonstrated that large scale, highly ordered monolayer films of gold-polystyrene (PS) nanospheres can be fabricated from PGN inks within a few seconds on surfaces with high interfacial energy using simple flow-coating. Herein, we extend this technique to the fabrication of mono and bilayer films of gold-PS nanorods, which unlike spheres requires both positional and orientational ordering. Using a combination of atomic force microscopy, scanning electron microscopy, and grazing incidence X-ray scattering, we find that the transition from isotropic to higher-degree order within the polymer-grafted nanorod assemblies depends on coupling between particle aspect ratio, polymer canopy, surface energy, and in-plane shear. By gaining an in depth understanding into the assembly of both spheres and rods separately, insights are gained into the processing of multicomponent assemblies such as sphere-rod combinations.

Fabrication of highly ordered polymer-grafted nanorod assemblies

255th National Meeting (2018)

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