Temperature-Induced Tunable Assembly of Columnar Phases of Nanorods

Abstract

We report on the assembly of gold nanorods functionalized with poly(ethylene glycol) in aqueous suspensions by electrostatic control and hydrogen bonds provided by polyelectrolyte linkers (i .e., interpolymer complexation processes). Small angle X-ray scattering reveals that the quality and stability of the assemblies into the hexagonal columnar phases increases with temperature. Our study shows that the lattice constant of the ordered structures is tunable over a wide range of values by the interplay between electrostatic and hydrophobic effects.

Interfacial and Bulk Assembly of Anisotropic Gold Nanostructures: Implications for Photonics and Plasmonics

“…The suspended NSts and their aggregates in the bulk of the solutions are characterized with SAXS following established procedures. 24,30,55 Results and Discussion 2D interfacial assembly of PEG-AuNTs and PEG-AuNOh X-ray reflectivity(XRR). Normalized X-ray reflectivity data, R/R F , are shown in panels (a) and (c) in Figure 3 for PEG-AuNTs and in Figure 4 for PEG-AuNOh under various controlled solvent conditions as indicated.…”

Distinct thermoresponsive behaviour of oligo- and poly-ethylene glycol protected gold nanoparticles in concentrated salt solutions

“…However, they do not induce 3D assembly into supercrystals. 26 Different strategies that include salt concentration, interpolymer complexation, pH and temperature changes demonstrate that the self-assembly of structures other than spheres is also possible as it has been observed for gold nanorods 29 and gold nanotriangles 30 grafted with an EGn polymer corona. In this work, we present a study of the stability of EGn-AuNPs formed with methoxy-terminated oligo-or poly-ethylene glycol of different chain length (Scheme 1).…”

“…22 Moreover, the steric hindrance generated by the reorganization of flexible hydrophilic polymer brushes during interparticle association is critical for the morphological selectivity in the assembly. 23 Taking advantage of the hydrophobic/hydrophilic tuneable characteristics of the PEG polymers depending on the experimental conditions, Vaknin et al have dedicate great efforts to elucidate the influence of different salt concentrations [24][25][26][27][28] and temperature of the suspensions [29][30][31] in the interfacial assembly of EGn-AuNPs. The addition of ions to the solution impinges a poor solvent character for the polymers that could provoke the self-assembly of the EGn-AuNPs and its phase separation.…”

Nanoparticle Assembly in High Polymer Concentration Solutions Increases Superlattice Stability

“…[ 1–3 ] In principle, the use of additives within the solution can provide additional design parameters to tune particle behavior by affecting the motion of the particles or the strength of the interactions driving their assembly. [ 4–12 ] While approaches that employ such a strategy (such as the addition of polymer to induce flocculation in colloidal dispersions) have been well‐studied, these methods are most commonly studied in the formation of disordered aggregates or close‐packed structures, and limited examples exist that fully explain how similar approaches can affect more robust or versatile assembly techniques capable of driving particle crystallization. Additionally, while numerous studies have focused on interactions between free particles and polymer in solution, interactions between nanoparticle assemblies and dissolved polymer chains remain an important area of investigation.…”