Nanosecond Time-Resolution Study of Gold Nanorod Rotation at the Liquid-Solid Interface

Area of Science:

• Surface science
• Nanotechnology
• Physical chemistry

Background:

• Nanorod adsorption can involve an anchored state with rotational freedom.
• Understanding nanorod rotation is key to particle-surface interactions.
• Previous studies suggested continuous rotation of gold nanorods on glass.

Purpose of the Study:

• To investigate the rotation dynamics of anchored gold nanorods on negatively charged glass surfaces.
• To clarify the nature of nanorod rotation following surface interactions.

Main Methods:

• Utilized nanosecond time-resolution studies.
• Observed gold nanorod interactions with negatively charged glass surfaces.

Main Results:

• Apparent continuous rotation is composed of numerous fast, intermittent rotations.
• Gold nanorods spend most time in weakly immobilized states.
• Transitions between immobilized states occur on a millisecond timescale, ~50x slower than in bulk solution.

Conclusions:

• Gold nanorod rotation on glass is not continuous but intermittent.
• Weakly immobilized states dominate nanorod-surface interactions.
• The study reveals a slower rotation mechanism than previously assumed.