Stabilization of emulsions using polymeric surfactants based on inulin

Area of Science:

• Colloid and Surface Chemistry
• Polymer Science
• Materials Science

Background:

• Polymeric surfactants are crucial for stabilizing emulsions.
• Understanding polymer adsorption at interfaces is key to emulsion stability.
• Steric stabilization relies on adsorbed polymer layers preventing droplet coalescence.

Purpose of the Study:

• To describe the classification, adsorption, and interfacial behavior of polymeric surfactants.
• To investigate the stabilization mechanism of oil-in-water emulsions using a novel inulin-based graft copolymer.
• To evaluate the emulsion stability under various electrolyte concentrations and temperatures.

Main Methods:

• Theoretical approaches for polymer adsorption.
• Experimental techniques for studying polymer adsorption and conformation at interfaces.
• Preparation and stability testing of oil-in-water emulsions with an inulin-based surfactant and cosurfactant (Span 20).
• Cloud point measurements to assess polymer hydration.

Main Results:

• A novel graft copolymeric surfactant based on alkyl-modified inulin was synthesized.
• Oil-in-water emulsions stabilized by this surfactant showed improved stability with Span 20 cosurfactant.
• Emulsions remained stable for over a year at 50°C in high NaCl (up to 2 mol dm⁻³) and MgSO₄ (up to 1 mol dm⁻³) concentrations.
• High hydration of the polyfructose chain was confirmed, contributing to stability via steric repulsion.

Conclusions:

• The inulin-based graft copolymer provides effective steric stabilization for oil-in-water emulsions.
• The observed high stability in electrolyte solutions is attributed to the highly hydrated polyfructose chains.
• This novel surfactant demonstrates potential for applications requiring stable emulsions in challenging environments.