Nanorod-Based Supramolecular Nanocomposites: Effects of Nanorod Length

Nanorods (NRs) have unique anisotropic properties that are desirable for various applications. Block copolymer based supramolecules present unique opportunities to control inter-rod ordering and macroscopic alignment of NRs to fully take advantage of their unique anisotropic properties. Here, we studied the effects of NR aspect ratio where the NR length is in the range of 20-180 nm on the assemblies of NRs in supramolecular framework. At a moderate loading (similar to 3 vol %), well-ordered assemblies of 37-90 nm NRs embedded in the supramolecular framework were formed. Shorter NRs (similar to 22 nm) coassemble with the supramolecule bot were not well-ordered and displayed little orientational control within the microdomains. In contrast,, longer NRs (similar to 180 nm) formed kinetically trapped states that restricted the formation of well-ordered coassemblies in NR/supramolecule blends. Additionally, the NRs are shown to be capable of kinetically trapping the system after normally reversible morphological transitions triggered by the thermal dissociation of the supramolecule, arresting the system away from a stable morphology. These studies shed light on the effects of NR-induced kinetic arrest on the self-assembly of a supramolecular nano composite.