Curvature-Directed Patch Formation on Gold Nanocubes by Thermally Induced Polymer Redistribution

Abstract

Patchy nanoparticles (NPs) enable directional interactions and dynamic structural transformations, yet controlling polymeric patch formation with high spatial precision remains a significant challenge. Here, a thermally driven approach is presented to forming polystyrene (PS) patches on low-curvature facets of anisotropic gold nanocubes (NCs) using a single polymer component. Heating in DMF above 90 degrees C triggers selective desorption of PS chains from high-curvature edges and vertices via Au & horbar;S bond dissociation, followed by migration and deposition into rounded patches on flat surfaces. The number and angular configuration of patches are governed by NP geometry and thermal energy, typically appearing at 90 degrees intervals. Patch morphology is highly responsive to NC concentration. Lower concentrations promote thicker convex patches, whereas higher concentrations suppress polymer rearrangement. Molecular dynamics simulations reproduce the curvature-sensitive detachment and asymmetric redistribution observed experimentally. Solvent polarity and core composition serve as additional tools to modulate patch formation. This study reveals a robust mechanism for curvature-directed polymer rearrangement and introduces a precise and scalable strategy for engineering patchy nanostructures. The ability to selectively pattern polymers onto specific nanoscale regions opens new opportunities for constructing programmable surfaces in plasmonics, catalysis, and anisotropic self-assembly.