Tunable Self-assembly of Au-nanoparticles with Near-Perfect Monodispersity

TL;DR

This paper demonstrates the tunable self-assembly of gold nanoparticles with near-perfect monodispersity on polystyrene films, controlled by film thickness and surface energy variations, enabling precise nanostructure fabrication.

Contribution

It introduces a method to control nanoparticle shape, size, and assembly on polymer films by adjusting film thickness and surface energy, achieving near-perfect monodispersity.

Findings

Nanoparticles self-assemble slowly at room temperature.

Surface diffusion is enhanced by confinement-induced layering.

Tuning film thickness controls nanoparticle properties.

Abstract

Au nanoparticles with near perfect monodispersity in shape and size self-assemble, very slowly and at room temperature, on polystyrene films for film thickness < 4R_{g}$, R_{g} being unperturbed polymer gyration radius. Nanoparticle shape and size can be tuned, without sacrificing monodispersity, by changing polymer film thickness. Self-assembly is caused by enhanced two-dimensional diffusion of sputter-deposited Au clusters on a distribution of surface energy variations, sharply defined and with tunable dimensions, corresponding to low cohesion between gyration spheres on film surface. Lowering of cohesion and enhanced surface diffusion are clearly related to confinement-induced gyration sphere layering along film depth.