Hygroscopy-induced nanoparticle reshuffling in ionic-gold-residue-stabilized gold suprananoparticles

Area of Science:

• Nanotechnology
• Materials Science
• Analytical Chemistry

Background:

• Conventional gold nanoparticle synthesis methods often yield particles with varying properties.
• Understanding the role of ionic precursors is crucial for controlling nanoparticle characteristics.
• Polyethyleneimine (PEI) is a polymer used for nanoparticle stabilization.

Purpose of the Study:

• To investigate the influence of ionic precursors on gold nanoparticle formation and properties.
• To explore the assembly of gold nanoparticles into suprananoparticles.
• To develop a novel method for water content detection using these suprananoparticles.

Main Methods:

• Synthesis of gold nanoparticles stabilized by Polyethyleneimine (PEI).
• Characterization of nanoparticle properties and assembly into suprananoparticles.
• Development and validation of a water detection method based on optical property changes.

Main Results:

• Ultra-small, nearly neutral gold nanoparticles were formed due to low gold availability and excess gold ions.
• PEI-stabilized gold nanoparticles assembled into stable suprananoparticles.
• Hygroscopic Au(iii) residues in suprananoparticles absorbed moisture, inducing nanoparticle reshuffling and optical property changes.

Conclusions:

• Ionic precursors significantly impact gold nanoparticle size, charge, and assembly.
• PEI-stabilized gold nanoparticle suprananoparticles exhibit unique water-responsive behavior.
• A sensitive and straightforward method for detecting water in organic solvents was successfully developed.