Structured liquids with interfacial robust assemblies of a nonionic crystalline surfactant

Area of Science:

• Materials Science
• Colloid and Surface Chemistry

Background:

• Structuring liquids involves kinetically trapping nonequilibrium shapes of liquid-liquid interfaces, crucial for all-liquid devices.
• Existing methods rely on colloidal particles or complex molecular/nanoparticle assemblies, but simple molecular surfactants are underexplored.

Purpose of the Study:

• To investigate the potential of a simple molecular surfactant with strong intermolecular interactions for liquid structuring.
• To demonstrate the formation of stable interfacial assemblies capable of solid-particle-like behavior.

Main Methods:

• Exploration of n-octyl cello-oligosaccharide, a nonionic surfactant with inherent crystalline assembly capabilities.
• Investigation of interfacial assembly at water-organic solvent interfaces using pendant drop tensiometry and emulsification.

Main Results:

• The crystalline surfactant self-assembled into a monolayer at interfaces, enabling arrested shape changes.
• Successfully created irregular liquid droplet shapes across diverse conditions, including various organic solvents and extreme pH/ionic strengths.

Conclusions:

• A novel nonionic crystalline surfactant can effectively structure liquids.
• This surfactant forms robust interfacial assemblies, offering a new strategy for creating stable, non-equilibrium liquid structures.