Orientational Ordering of Passivating Ligands on CdS Nanorods in Solution Generates Strong Rod–Rod Interactions

We present the first nearly atomistic molecular dynamics study of nanorod–nanorod association in explicit solvent, showing that inter-rod forces can be dominated by microscopic factors absent in common continuum descriptions. Specifically, we find that alkane ligands on faceted CdS nanorods in <i>n</i>-hexane undergo a temperature-dependent order–disorder transition akin to that of self-assembled monolayers on macroscopic substrates. This collective ligand alignment organizes nearby solvent molecules, strongly influencing the statistics of rod–rod separation. The strong temperature dependence of this mechanism could be exploited in the laboratory to manipulate and optimize the assembly of ordered structures