Hierarchical Fullerene Assembly: Seeded Coprecipitation and Electric Field Directed Assembly

Abstract

Hierarchical C colloidal films are assembled from nanoscale to macroscale. Fullerene molecular crystals are grown via seeded cosolvent precipitation with mixed solvent [tetrahydronaphthalene (THN)/trimethylpyridine (TMP)] and antisolvent 2-propanol. The fullerene solutions are aged under illumination, which due to the presence of TMP reduces the free monomer concentration through fullerene aggregation into nanoparticles. The nanoparticles seed the growth of monodisperse fullerene colloids on injection into the antisolvent. Diverse colloidal morphologies are prepared as a function of injection volume and fullerene solution concentration. The high fullerene solubility of THN enables C colloids to be prepared in quantities sufficient for assembly (5 × 10 ). Electric fields are applied to colloidal C platelets confined to two dimensions. The particles assemble under dipolar forces, dielectrophoretic forces, and electrohydrodynamic flows. Frequency-dependent phase transitions occur at the critical Maxwell-Wagner crossover frequency, where the effective polarizability of the particles in the medium is substantially reduced. Structures form as a function of field strength, frequency, and confinement including hexagonal, oblique, string fluid, coexistent hexagonal-rhombic, and tetratic.

Asymmetric Fullerene Nanosurfactant: Interface Engineering for Automatic Molecular Alignments

“…[17,18] The enhancement of intermolecular interactions between nanoparticles and LC molecules achieved by chemical modi fication does not necessarily result in the materials with maximally improved physical properties, since functional groups on the nanoparticle surface are randomly distri buted. [19,20] Thus, materials with poorly defined structures and morphologies can limit the formation of uniform LC alignment. [21] To keep pace with the rapid changes in the evergrowing sophistication of mole cular design, chemical functions should be introduced into nanoparticles in a programmed manner.…”

“…To overcome the notorious aggregation of nanoparticles in the anisotropic LC media, various methods for achieving automatic LC alignment have been developed, including functionalized nanoparticles referred to as organic–inorganic hybrid materials . The enhancement of intermolecular interactions between nanoparticles and LC molecules achieved by chemical modification does not necessarily result in the materials with maximally improved physical properties, since functional groups on the nanoparticle surface are randomly distributed . Thus, materials with poorly defined structures and morphologies can limit the formation of uniform LC alignment .…”

Solution Processable 1D Fullerene C60 Crystals for Visible Spectrum Photodetectors

“…In recent years, significant advancements have been achieved in regard to their application in photonic devices. For example, their thermal conversion into nanoporous carbon tubes, control over shape and size, their surfactant free preparation, along with their hierarchical assembly that ranges from the nanoscale to the macroscale . Their use in a wide variety of applications has also been demonstrated successfully, though their utilization in commercial devices still remains limited.…”

Remote-controllable and encryptable smart glasses: a photoresponsive azobenzene molecular commander determines the molecular alignments of liquid crystal soldiers

“…1,31 Although the LC command surface prepared by giant surfactants is valuable and versatile, several drawbacks such as poor solubility in LC medium, selfaggregation, and unstable surface adhesion are considered as obstacles for practical use. [46][47][48][49][50] Surface treatment to create chemical bonds between substrates and photoresponsive molecules can break through the difficulties of photoresponsive LC command systems using giant surfactants. The introduction of silane coupling agents to hydroxylated substrates is most widely used for the chemical modification of surfaces.…”