Title: Faceted particles formed by the frustrated packing of anisotropic colloids on curved surfaces
Speaker: Dr. Abhijit Ghosh, Brandeis University, Massachusetts, USA
Venue: IOP Lecture Hall
Date: 2017-Feb-13 16:00:00
Abstract: We use computer simulations and simple theoretical models to analyze the morphologies
that result when rod-like particles end-attach onto a curved surface, creating a finite thickness
monolayer aligned with the surface normal. This geometry leads to two forms
of frustration, one associated with the incompatibility of hexagonal order on surfaces
with Gaussian curvature, and the second reflecting the deformation of a layer
with finite thickness on a surface with non-zero mean curvature. We show that the latter
effect leads to a faceting mechanism. Above threshold values of inter-particle attraction
strength and surface mean curvature, the adsorbed layer undergoes a transition from
orientational disorder to an ordered state that is demarcated by reproducible patterns of
line defects. The number of facets is controlled by the competition between line
defect energy and intra-facet strain. Tuning control parameters thus leads to a rich variety
of morphologies, including icosahedral particles and irregular polyhedra. In addition to
suggesting a new strategy for the synthesis of aspherical particles with tunable
symmetries, our results may shed light on recent experiments in which rod-like HIV
GAG proteins assemble around nanoscale particles.
Reference :
Faceted particles formed by the frustrated
packing of anisotropic colloids on curved surfaces
Naiyin Yu,†Abhijit Ghosh†and Michael F. Hagan*
Soft Matter, 12, 8990 – 8998, (2016)
(Selected as internal cover article)
