Size limitations for the formation of ordered striped nanoparticles

Area of Science:

• Nanotechnology and Materials Science
• Surface Chemistry and Self-Assembly

Background:

• Gold nanoparticles (NPs) functionalized with immiscible molecules in their ligand shells can undergo phase separation.
• This phase separation results in unique rippled structures within the ligand shell.
• Such structural organization has potential for directing nanoparticle assembly.

Purpose of the Study:

• To investigate the size-dependent formation of rippled ligand shell structures on gold nanoparticles.
• To determine the specific size range of gold NPs that facilitates chain assembly via ligand-induced phase separation.
• To correlate the observed rippled morphology with nanoparticle size and assembly behavior.

Main Methods:

• Experimental synthesis and characterization of gold nanoparticles with mixed immiscible ligands.
• Microscopy techniques to observe nanoparticle assembly into chains.
• Computational simulations to model ligand arrangement and morphology on NPs of varying sizes.

Main Results:

• Gold nanoparticles within a specific size range were observed to assemble into ordered chains.
• The rippled morphology of the ligand shell was found to be exclusively present in NPs within this size range.
• Simulations confirmed the size-dependent nature of the ligand shell's rippled structure.

Conclusions:

• The formation of rippled ligand shell structures and subsequent nanoparticle chain assembly are critically dependent on nanoparticle size.
• A defined size window exists for gold nanoparticles to exhibit both the rippled ligand morphology and self-assembly into chains.
• These findings provide crucial insights into controlling nanoparticle organization through ligand shell engineering.