Symmetry-Breaking Patch Formation on Triangular Gold Nanoparticles*

Synthesizing patchy particles with predictive control over patch size, shape, placement and number is a holy grail of nanoparticle assembly research. Here, using gold triangular nanoprisms and polystyrene-b-polyacrylic acid as a model system, we show that polymers can be driven to selectively adsorb onto different surface locations on nanoparticles, resulting in patchy nanoparticles with broken symmetry. We rationalize the underlying assembly mechanism using scaling theories that accurately predict our experimental observations at all levels – from particle-level patch pattern, nanoscopic size and shape of patches, to the self-limited assemblies. Both experimental strategies and theoretical predictions readily extend to particles of other shapes. Our work provides a novel approach to leverage polymer interaction with nanoscale surfaces to drive asymmetric grafting in functional nanomaterials.