Droplet clustering in cyclodextrin-based emulsions mediated by methylcellulose

Area of Science:

• Materials Science
• Colloid and Surface Chemistry
• Rheology

Background:

• Cyclodextrin (CD)-stabilized emulsions often suffer from rapid droplet aggregation, limiting their use as templates.
• Controlling emulsion microstructure and stability is crucial for advanced material design.

Purpose of the Study:

• To investigate the impact of methylcellulose (MC) on the microstructure and stability of CD-stabilized emulsions.
• To explore the rheological properties and viscoelastic nonlinearities of these complex fluid systems.

Main Methods:

• Formulation of emulsions with varying MC concentrations and molecular weights.
• Microstructural analysis using optical microscopy, laser particle analysis, and confocal laser scanning microscopy.
• Rheological characterization via large amplitude oscillatory shear and Lissajous-Bowditch plots.

Main Results:

• Emulsion droplets form small clusters, largely independent of MC concentration and molecular weight.
• Viscoelastic properties and nonlinear behavior confirm the observed clustering pattern.
• Evidence suggests simultaneous depletion flocculation and kinetic trapping by MC cause this phenomenon.

Conclusions:

• Methylcellulose (MC) induces a glass-like dynamic arrest in cyclodextrin (CD)-stabilized emulsions.
• The formation of stable, small equilibrium droplet clusters is a key finding.
• This controlled clustering offers potential for improved emulsion templating applications.