Nanoparticle adhesion at liquid interfaces

Area of Science:

• Interface Science
• Nanotechnology
• Surface Chemistry

Background:

• Nanoparticle adhesion at liquid interfaces is vital for applications such as drug delivery, aerosol adsorption, and self-assembly.
• Quantitative nanoscale measurements of these capillary interactions are challenging, with existing data primarily at larger scales.

Purpose of the Study:

• To investigate nanoparticle adhesion and removal from liquid interfaces.
• To determine the influence of particle geometry and wettability on adhesion forces.
• To bridge the gap between experimental measurements and theoretical predictions at the nanoscale.

Main Methods:

• Utilized atomic force microscopy (AFM) with controlled conical tip geometries to mimic nanoparticle nano-asperities.
• Employed continuum modeling with Surface Evolver software for interface visualization and energy minimization.
• Validated experimental findings with computational simulations.

Main Results:

• Demonstrated quantitative agreement between AFM experiments and continuum simulations, validating nanoscale thermodynamics.
• Established that surface tension is the primary driver of nanoparticle adhesion, with minimal line tension contribution.
• Identified particle geometry as the key factor influencing capillary bridge rupture and adhesion force profiles, alongside liquid contact angle.

Conclusions:

• Continuum thermodynamics principles are applicable down to the nanoscale for understanding nanoparticle-liquid interface interactions.
• Particle shape and wettability are critical design parameters for controlling adhesion at liquid interfaces.
• Findings can inform the design of smart interfaces for targeted particle manipulation in various applications.