Pickering emulsions stabilized by β-CD microcrystals: Construction and interfacial assembly mechanism

Area of Science:

• Materials Science
• Colloid and Surface Science

Background:

• Beta-cyclodextrin (β-CD) forms amphiphilic inclusion complexes (ICs) with guest molecules, stabilizing oil-water interfaces.
• These ICs can reduce interfacial tension and stabilize Pickering emulsions, but β-CD's subtle changes during preparation are often overlooked.

Purpose of the Study:

• To investigate the self-assembly and formation mechanism of β-cyclodextrin and ginger oil (GO) inclusion complexes.
• To elucidate the role of these complexes in stabilizing GO Pickering emulsions without exogenous emulsifiers.

Main Methods:

• Preparation of Pickering emulsion using high-speed shearing homogenization of β-CD and GO.
• Characterization of emulsion stability via microscopic observation, staining analysis, and creaming index (CI).
• Preparation of GO/β-CD ICs by ball milling, analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR).

Main Results:

• The prepared Pickering emulsion exhibited serious flocculation with rough droplet surfaces and lamellar particles.
• β-CD and GO formed nanoscale amphiphilic ICs via host-guest interaction.
• These nanoscale ICs further self-assembled into lamellar micron-scale amphiphilic ICs microcrystals.

Conclusions:

• The study clarifies the formation process of lamellar particles in GO/β-CD Pickering emulsions.
• Amphiphilic ICs and their microcrystals aggregate at the oil-water interface, stabilizing the emulsion.
• Findings provide a theoretical basis for developing high-performance β-CD-stabilized Pickering emulsions.