One-step processing of highly viscous multiple Pickering emulsions

Area of Science:

• Colloid and Surface Science
• Materials Science
• Chemical Engineering

Background:

• Solid-stabilized Pickering emulsions offer surfactant-free and stable alternatives to conventional emulsions.
• Understanding the influence of liquid phase viscosity on Pickering emulsion processing is crucial for chemical engineering applications.
• Previous assumptions suggested increased viscosity would decrease the emulsified dispersed phase.

Purpose of the Study:

• To investigate the formation of Pickering emulsions using high viscosity silicone oils.
• To elucidate the role of particle properties and oil viscosity in stabilizing multiple emulsions.
• To develop a simple, component-efficient method for preparing stable W/O/W Pickering emulsions.

Main Methods:

• Utilized very high viscosity silicone oils (≥10,000 cSt).
• Employed sub-μm silica particles modified with two grafted silanes and sodium alginate.
• Achieved double water-in-oil-in-water (W/O/W) Pickering emulsion formation in a single processing step.

Main Results:

• Successfully produced double water-in-oil-in-water (W/O/W) Pickering emulsions in one step.
• Observed phase inversion mechanism for water sub-inclusion formation.
• Demonstrated that high oil viscosity and particle layers stabilize sub-inclusions by limiting mobility and acting as barriers.

Conclusions:

• High viscosity is key to forming stable W/O/W Pickering emulsions via phase inversion.
• The developed method is simple, requires minimal components, and is effective for sensitive compound encapsulation.
• These emulsions have potential applications in the protection and transport of encapsulated substances.