Stimuli-Responsive Biomass Cellulose Particles Being Able to Reversibly Self-Assemble at Fluid Interface.

Area of Science:

• Materials Science
• Colloid and Surface Chemistry
• Biomaterials Engineering

Background:

• Microcrystalline cellulose (MCC) is a renewable biomass material with potential applications in emulsions and foams.
• Developing stimuli-responsive and self-assembling particulate materials is crucial for advanced applications.
• Controlling particle surface properties is key to achieving desired functionalities like emulsion stabilization.

Purpose of the Study:

• To develop stimuli-responsive surface-active microcrystalline cellulose (MCC) particles.
• To investigate the mechanism of reversible hydrophobization and dehydrophobization of MCC particles.
• To explore the application of these modified MCC particles in forming reversible oil-in-water (O/W) Pickering emulsions.

Main Methods:

• Hydrophobization of MCC particles using cationic surfactants (e.g., CTAB) via electrostatic adsorption.
• Dehydrophobization triggered by the addition of anionic surfactants (e.g., SDS) due to stronger surfactant-surfactant interactions.
• Formation and characterization of reversible O/W Pickering emulsions using modified MCC particles and trace amounts of ionic surfactants.

Main Results:

• Stimuli-responsive surface-active MCC particles were successfully synthesized.
• Reversible changes in MCC particle hydrophobicity were achieved by alternating addition of cationic and anionic surfactants.
• Reversible O/W Pickering emulsions were formed, with longer alkyl chain anionic surfactants enhancing demulsification efficiency.

Conclusions:

• Surface-modified MCC particles exhibit stimuli-responsive behavior, enabling reversible emulsion formation.
• The mechanism involves tunable electrostatic interactions and surfactant-surfactant pairing.
• These biocompatible, biodegradable, and renewable particles are promising for applications in emulsions and foams.