Forming Supramolecular Networks from Nanoscale Rods in Binary, Phase-Separating Mixtures

Abstract

Simulations show that when low-volume fractions of nanoscale rods are immersed in a binary, phase-separating blend, the rods self-assemble into needle-like, percolating networks. The interconnected network arises through the dynamic interplay of phase-separation between the fluids, through preferential adsorption of the minority component onto the mobile rods, and through rod-rod repulsion. Such cooperative effects provide a means of manipulating the motion of nanoscopic objects and directing their association into supramolecular structures. Increasing the rod concentration beyond the effective percolation threshold drives the system to self-assemble into a lamellar morphology, with layers of wetted rods alternating with layers of the majority-component fluid. This approach can potentially yield organic/inorganic composites that are ordered on nanometer scales and exhibit electrical or structural integrity.

Conductivity of carbon nanotube polymer composites

“…This implies that there is a range of CNT-loading, which will form a percolating network in the fluid mixture but not in the pure "ideal" fluid A. In addition, the CNTs themselves can significantly influence the fluid morphology, which can further aid in the formation of percolating networks [10]. In contrast, the morphologies resulting from diblock copolymers are somewhat rigid.…”

“…Thus, with appropriate choice of polymers more structured arrangements with improved percolation of CNTs at low fractions might be possible.. Template-controlled assembly of CNTs is a problem relevant not only to nanocomposites, but to other diverse application areas [6]. Self-organization of inorganic nanoparticles in copolymers have been investigated both experimentally [7] and computationally [8,9] and dispersion of stiff rods, somewhat representative of CNTs, have been investigated in fluids and phase-separating fluid mixtures [10].…”

End-to-End Alignment of Nanorods in Thin Films

“…Slowing or arrest of the system during the assembly process results in reduced grain sizes 44 and increased defect concentration. 45 Kinetic trapping may also prevent the coassembly of NRs and supramolecule even though the NR assembly is energetically favorable.…”

Colloidal Jamming at Interfaces: A Route to Fluid-Bicontinuous Gels

“…The previously preferred route to particle-stabilised emulsions involves agitation of immiscible fluids and does not appear to favour bicontinuity [9]. Other related work [6,30,31,32] involves particles with a strong preference for one of the two liquids, creating a particle network within the chosen liquid rather than at the interface.…”