  Advances in synthetic methods have spawned an array of nanoparticles and
bio-inspired molecules of diverse shapes and interaction geometries. Recent
experiments indicate that such anisotropic particles exhibit a variety of
'nonclassical' self-assembly pathways, forming ordered assemblies via
intermediates that do not share the architecture of the bulk material. Here we
apply mean field theory to a prototypical model of interacting anisotropic
particles, and find a clear thermodynamic impetus for nonclassical ordering in
certain regimes of parameter space. In other parameter regimes, by contrast,
assembly pathways are selected by dynamics. This approach suggests a means of
predicting when anisotropic particles might assemble in a manner more
complicated than that assumed by classical nucleation theory.
