Modulating the Spontaneous Adsorption of Lignin Nanoparticle at Oil-Water Interfaces

Area of Science:

• Colloid and Surface Science
• Materials Science
• Green Chemistry

Background:

• Pickering emulsions are stabilized by particles, with synthetic particles raising environmental concerns.
• Lignin nanoparticles (LNPs), derived from industrial byproducts, are explored as eco-friendly stabilizers.
• LNPs possess unique surface chemistry and morphology, suggesting potential for effective interfacial adsorption.

Purpose of the Study:

• To investigate the influence of colloidal parameters on LNP adsorption at oil-water interfaces.
• To determine optimal conditions for LNP-stabilized Pickering emulsions.
• To evaluate the long-term stability of emulsions stabilized by LNPs.

Main Methods:

• Dynamic interfacial tension analysis was used to study LNP adsorption at hexadecane-water and rapeseed oil-water interfaces.
• Various colloidal parameters (LNP type, oil-water system, pH, concentration, ionic strength) were systematically varied.
• Optimized conditions were applied to prepare and test the stability of Pickering emulsions.

Main Results:

• LNPs exhibited spontaneous adsorption at oil-water interfaces, unlike many synthetic particles.
• LNP adsorption was significantly influenced by colloidal parameters, with pH being a key factor.
• Greatest LNP adsorption was observed at higher pH values.
• Emulsions stabilized with LNPs at pH 8.0 remained stable even after a pH decrease to 5.0.

Conclusions:

• LNPs are effective, spontaneously adsorbing stabilizers for Pickering emulsions.
• Colloidal parameters, especially pH, critically control LNP interfacial adsorption and emulsion performance.
• Lignin nanoparticles offer a promising biobased alternative for sustainable Pickering emulsion stabilization.