Size control of aggregations via self-assembly of amphiphilic gold nanoparticles

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Vol. 538; pp. 574 - 582
• Main Authors: Jang, Hyun-Jun, Lee, Hee-Young
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05-02-2018
• Subjects: Amphiphilic gold nanoparticles; Mixed monolayers; Self-assembly; Surfactants; Mixed monolayers; Self-assembly; Surfactants; Amphiphilic gold nanoparticles
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2017.11.057

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A simple and reliable method is described to create aggregated structures of gold nanoparticles (AuNPs) with a tunable size in water. The surface of the AuNPs is covered with mixed monolayers of hydrophobic and hydrophilic ligands, and aggregations of the AuNPs with an irregularly spherical shape are induced by the self-assembly of AuNPs due to hydrophobic and electrostatic interactions. Here, two ligands on the AuNP surface are not fixed but are rearranged for the formation of the AuNP aggregations. The sizes of the aggregations can be easily tuned by varying the molar ratio of the hydrophobic and hydrophilic ligands used. Changes in the sizes of the structures are systematically characterized by transmission electron microscope (TEM) and dynamic light scattering (DLS). A red-shift of the wavelength from UV–vis spectroscopy data and a color change from pale red to pale purple closely related to the surface plasmon resonance of the AuNPs also confirm the aggregation of AuNPs.