Stabilizing Bicontinuous Emulsions with Sub-Micrometer Domains Solely by Nanoparticles

Area of Science:

• Materials Science
• Colloid and Surface Chemistry

Background:

• Bicontinuous interfacially jammed emulsion gels (bijels) are promising for applications like batteries and membranes.
• Current methods for creating sub-micrometer bijel domains require surfactants, hindering synthesis and postprocessing.
• Surfactants complicate the development of bijels into functional nanomaterials.

Purpose of the Study:

• To develop surfactant-free bijels with sub-micrometer liquid domains.
• To demonstrate nanoparticle-only stabilization of bijels.
• To enable simpler synthesis and broader applications of bijel nanomaterials.

Main Methods:

• Covalent surface functionalization of silica nanoparticles was characterized using TGA, MS, FTIR, and contact angle measurements.
• Bijels were synthesized using functionalized nanoparticles via solvent transfer induced phase separation (STrIPS).
• Nanoparticle functionalization and surface ionization were optimized for bijel stabilization.

Main Results:

• Surfactant-free bijels with sub-micrometer liquid domains were successfully synthesized.
• Nanoparticles with intermediate functionalization and controlled negative surface charge were found to be optimal stabilizers.
• The STrIPS method allowed precise control over nanoparticle properties for bijel formation.

Conclusions:

• This work introduces a novel method for creating surfactant-free, nanoparticle-stabilized bijels.
• Achieving sub-micrometer domains without surfactants simplifies bijel synthesis and processing.
• This advancement facilitates the use of bijels in diverse nanomaterial applications.