Investigation into the Interaction between Surface-Bound Alkylamines and Gold Nanoparticles

Area of Science:

• Nanomaterials Science
• Surface Chemistry
• Inorganic Chemistry

Background:

• Alkylamines are explored as capping agents for gold nanoparticles (AuNPs).
• Understanding alkylamine interaction with gold surfaces is crucial but limited.
• Previous studies focused on alkanethiols and phosphine derivatives.

Purpose of the Study:

• To investigate the binding modes of alkylamines on gold nanoparticle surfaces.
• To characterize gold nanoparticles capped with laurylamine (LAM) and octadecylamine (ODA).
• To elucidate the interaction mechanisms between alkylamines and the gold support.

Main Methods:

• Fourier transform infrared spectroscopy (FTIR)
• Thermogravimetry (TGA)
• Nuclear magnetic resonance (NMR)
• X-ray photoemission spectroscopy (XPS)

Main Results:

• Two distinct binding modes of alkylamines on gold nanoparticles were identified.
• A weakly bound component suggests an electrostatic complex with surface ions.
• A strongly bound species is tentatively assigned to a [AuCl(NH2R)] complex.
• Alkylamine monolayers can undergo place exchange with other amines.

Conclusions:

• Alkylamines bind to gold nanoparticles via dual mechanisms, offering insights into surface functionalization.
• The findings contribute to a deeper understanding of amine-capping on gold nanoparticles.
• The potential for place exchange opens avenues for modifying nanoparticle properties.