Pickering stabilization of double emulsions: Basic concepts, rationale, preparation, potential applications,...

Area of Science:

• Colloid and Surface Science
• Materials Science
• Emulsion Technology

Background:

• Double emulsions (DEs) possess unique compartmentalized structures but suffer from inherent instability.
• Conventional stabilization methods using low-molecular-weight (LMW) surfactants often present limitations.
• Pickering stabilization, utilizing solid particles, offers a promising alternative for enhancing DE stability.

Purpose of the Study:

• To clarify the precise definition and application of Pickering stabilization in the context of double emulsions.
• To review the mechanisms, preparation methods, and interfacial properties of Pickering double emulsions (PDEs).
• To examine the potential applications and identify current challenges for industrial implementation of PDEs.

Main Methods:

• Review of literature on Pickering stabilization and double emulsions.
• Analysis of particle properties (dual wettability, high desorption energy) for interfacial adsorption.
• Examination of various preparation techniques including two-step, one-step, and microfluidic methods.

Main Results:

• Solid particles irreversibly adsorb at interfaces, forming robust barriers that prevent droplet coalescence and internal phase escape.
• Pickering stabilization overcomes limitations associated with LMW surfactants in DEs.
• PDEs enable sophisticated functionalities like co-encapsulation, controlled release, and hierarchical structure formation.

Conclusions:

• Pickering double emulsions offer superior stability and functionality compared to conventional DEs.
• Further research is needed to eliminate surfactant use, develop sustainable particles, and scale up production.
• Addressing these challenges will unlock the full industrial potential of PDEs.