Chitin nanocrystals: A promising alternative to synthetic surfactants for stabilizing oil-in-water emulsions

Oil-in-water emulsions are used in a variety of applications, but they are often unstable and can break down over time due to different mechanisms such as flocculation and coalescence, as well as gravitational separation, like creaming and sedimentation, which can occur either independently or concurrently. This study investigated the utilize of chitin nanocrystals (ChiNCs) as stabilizers for O/W emulsions which is derived from a green and renewable material. ChiNCs were produced by acid hydrolysis of chitin powder. The ChiNC's TEM results showed a needle-like morphology with a length of 200–800 nm and a width of 20–80 nm. The surface charge of ChiNCs is negative at pH > 7 and positive at pH < 7. The rheological properties of O/W emulsions stabilized by ChiNCs were compared with those stabilized by synthetic surfactants Tween 80 and CTAB. ChiNC-stabilized emulsions had a higher yield stress and a lower shear viscosity than emulsions stabilized by synthetic surfactants, which makes them more stable and less likely to break down. This suggests that ChiNCs are a promising alternative to synthetic surfactants for stabilizing O/W emulsions.