Stable Cellulose Nanofibril Microcapsules from Pickering Emulsion Templates.

Area of Science:

• Materials Science
• Colloid and Surface Chemistry

Background:

• Electrostatic attractions are crucial for complex formation between oppositely charged nanofibrils.
• Cellulose nanofibrils (CNFs) offer unique properties for material development.
• Pickering emulsions (PEs) are stabilized by solid particles at the oil-water interface.

Purpose of the Study:

• To develop a novel method for producing microcapsules (MCs) using cellulose nanofibrils.
• To investigate the role of electrostatic interactions between cationized cellulose nanofibril (CCNF) and oxidized cellulose nanofibril (OCNF) in microcapsule formation.
• To evaluate the encapsulation and release properties of the prepared microcapsules.

Main Methods:

• Stabilization of Pickering emulsions using cationized cellulose nanofibril (CCNF).
• Induction of electrostatic interactions by adding oxidized cellulose nanofibrils (OCNF) at the oil-water interface.
• Encapsulation of Nile red (NR) in sunflower oil (SFO) droplets.
• Scale-up of microcapsule preparation using membrane emulsification.

Main Results:

• CCNF-stabilized PEs were successfully formed.
• The addition of OCNF induced electrostatic interactions, enhancing interface solidity and forming microcapsules.
• Nile red (NR) was effectively encapsulated within sunflower oil (SFO) droplets.
• The microcapsules demonstrated a low and controlled release of NR at room temperature.
• Membrane emulsification enabled scalable production of CCNF/OCNF complex network microcapsules.

Conclusions:

• Oppositely charged cellulose nanofibrils can effectively form stable microcapsules.
• The electrostatic complexation of CCNF and OCNF provides a robust interface for encapsulation.
• The developed method is suitable for scalable production of microcapsules with controlled release properties.