Fabrication of Oriented Colloidal Crystals from Capillary Assembly of Polymer‐Tethered Gold Nanoparticles

Abstract

Self‐assembled colloidal crystals (CCs) or nanoparticle (NPs) superlattices have attracted significant attention due to their potential applications in many fields. However, due to the complex interactions that govern the self‐assembly, it is difficult to predict and control the superstructure organization of CCs. Herein, a facile yet effective way is demonstrated to fabricate oriented CCs from capillary assembly of polymer‐tethered gold NPs (AuNPs). Assembly mechanism of polymer‐tethered AuNPs and their superlattice structures are systematically studied by in situ small‐angle X‐ray scattering (SAXS) technology. The results show that the oriented CCs of polymer‐tethered AuNPs can be obtained upon solvent evaporation in a capillary tube and the oriented structure is mainly determined by the chain length of polymer ligands and size of AuNPs. Assembly of AuNPs tethered by short‐chain ligand can result in oriented face‐centered cubic (fcc) superlattice, whereas AuNPs tethered by long‐chain ligand can assemble into an oriented body‐centered tetragonal (bct) superlattice structure. Interestingly, in situ SAXS study shows that for the sample of bct superlattice structure, a transformation from fcc to bct superlattice upon solvent evaporation is observed, which strongly depends on chain length of ligands. This work provides a useful guide for polymer‐tethered AuNPs to prepare orientation colloidal crystals.

Dynamic Assembly of Polymer-Tethered Gold Nanoparticles into a 2D Superlattice at the Air–Liquid Interface: Influence of the Polymer Structure and Solvent Vapor

“…AuNP Synthesis and Surface Modification. The Turkevich procedure 34,51 was used to make citrate-stabilized gold NPs (AuNPs) with a diameter of 15 nm. In 100 mL of water, 2.5 mL of HAuCl 4 (10 mM) was added and heated to boiling followed by addition of 30 mg of sodium citrate.…”

The Effect of Mesogenic Coronas on the Type and Anisotropy of Gold Nanoparticle Superlattices: When Can the Tail Wag the Dog?

“…In some cases where the gold core has uniform and well‐defined polyhedral shape and size, such shapes also affects the overall packing [9] . Preparation methods like solvent evaporation, [5c] solvent vapour annealing, [10] annealing at elevated temperature, [11] or controlling reduction speed [12] have different efficiencies in developing an ordered structure. In some cases changing preparation methods can also lead to a different polymorphs [6c] .…”

“…Most of the systems of NPs grafted with linear chains were precipitated from solution and studied by TEM, while structure formation in the bulk of these systems is often hampered by their glassy nature when dry. In systems of particles of a single type, by far the most common superstructures are face‐centred cubic (FCC) [5a,c,6c,14] hexagonal close packing (HCP) [5a,6c,15] and, with long grafted chains, body‐centred cubic (BCC)/body‐centred tetragonal (BCT), [5c,8c,11,14] or the even more densely packed hexagonal Frank–Kasper C14 phase [8c,16] …”

Effect of Polymeric Ligand Grafting Region on Confined Assembly of Gold Nanorods in cylindrical nanopores

“…The confined assembly method entails the imposition of spatial constraints on one or more dimensions during the assembly process, resulting in the ordered arrangement of the assembled primitives under the constraint effect [17,22] . This method effectively reduces the influence of external environmental factors on the assembly process, facilitating the system to surmount the energy barrier and generate long‐range ordered structures [2,22–25] . By manipulating the confinement strength via altering the confined space, one can regulate the assembly‘s arrangement and fabricate a range of nanomaterials with intricate structures [9,26] …”

“…[17,22] This method effectively reduces the influence of external environmental factors on the assembly process, facilitating the system to surmount the energy barrier and generate long-range ordered structures. [2,[22][23][24][25] By manipulating the confinement strength via altering the confined space, one can regulate the assembly's arrangement and fabricate a range of nanomaterials with intricate structures. [9,26] In confined spaces, NP morphology is a critical factor affecting the assembly process.…”