Linking Structure and Optical Properties of Plasmonic Nanoparticles on Tunable Spherical Surfaces

Area of Science:

• Materials Science
• Nanotechnology
• Soft Matter Physics

Background:

• Plasmonic nanoparticles (NPs) and thermoresponsive microgels form hybrid systems with tunable optical properties.
• Investigating NP organization on curved surfaces is crucial for biology and materials science but lacks nanoscale understanding.
• Microscopic mechanisms of NP spatial organization during microgel volume phase transitions (VPTs) remain unclear.

Purpose of the Study:

• To elucidate the mechanisms governing nanoparticle spatial organization during microgel VPT.
• To establish a link between microgel VPT, nanoparticle interactions, and plasmon coupling.
• To enable fine control over the plasmonic response of hybrid nanomaterials.

Main Methods:

• Combined small-angle X-ray scattering (SAXS) with advanced simulations.
• Developed a simple toy model to reproduce experimental data.
• Investigated nanoparticle redistribution and ordering during temperature-induced microgel collapse.

Main Results:

• Microgel VPT was shown to control NP-NP interactions.
• Temperature-induced microgel collapse drives NPs to the periphery, promoting surface ordering.
• A direct link between interparticle distance and plasmon coupling was quantitatively established.
• Structural and optical experimental data were successfully reproduced by the toy model.

Conclusions:

• Microgel VPT offers a route to control NP organization on curved nanoscale surfaces.
• This control allows for fine-tuning of plasmonic properties in hybrid materials.
• The findings open avenues for investigating nanoscale phase transitions and their optical consequences.