Multiscale physicochemical characterization of nanoemulsion organization

Through careful component selection and identification of critical formulation variables, we successfully prepared nanoemulsions containing high concentrations of thyme oil, overcoming typical instability issues.
The addition of Neem oil induces a modification of the viscosity of the oil phase, allowing for the stabilization of nanoemulsions with a lower amount of surfactant, reinforcing their potential as sustainable solutions. The amount of surfactant is further reduced by the replacement of a high-HLB emulsifier (soy lecithin) with Tween.
The study also highlighted the importance of considering dilution effects not only in terms of analytical accuracy but also with respect to structural behavior. Dilution, required to perform techniques such as DLS, can significantly alter the microstructure of the system depending on its composition and preparation method.