Catching the wave: particle transport by a moving phase boundary.

Area of Science:

• Soft Matter Physics
• Materials Science
• Physical Chemistry

Background:

• Non-equilibrium particle transport in liquid crystals (LCs) drives the formation of complex composite morphologies like capsules, foams, and gels during phase transitions.
• The underlying mechanisms governing this structure formation are not well understood.

Purpose of the Study:

• To elucidate the initial stages of nanoparticle transport at a moving LC phase boundary.
• To develop a fundamental model predicting particle behavior during phase transitions.

Main Methods:

• Coupling liquid crystal (LC) physics with the Fokker-Planck equation to model nanoparticle transport.
• Analyzing particle dynamics at a moving isotropic to nematic phase boundary.
• Utilizing fluorescence imaging for experimental validation.

Main Results:

• Identified two distinct transport regimes: particles surfing on or being swept up by the moving phase boundary.
• Established an analogy between LC-nanocomposite formation and chemotaxis.
• Demonstrated successful prediction of experimental observations through the developed model.

Conclusions:

• The model provides crucial insights into out-of-equilibrium transport phenomena.
• Understanding these mechanisms enhances the selection and control of phase transition-driven structures.
• This work enriches the understanding of how complex composite materials self-assemble.