Structural Characterization of Pluronic Micelles Swollen with Perfume Molecules

Area of Science:

• Polymer Science
• Physical Chemistry
• Materials Science

Background:

• Nonionic polymer micelles like Pluronic F127 are utilized in drug delivery and nanotechnology.
• Understanding the interaction of active compounds with micellar structures is crucial for formulation development.

Purpose of the Study:

• To investigate the insertion behavior and interaction mechanisms of essential oils within Pluronic F127 micelles.
• To elucidate the thermodynamic and structural consequences of essential oil incorporation.

Main Methods:

• Differential scanning calorimetry (DSC) for thermodynamic analysis.
• Small-angle X-ray scattering (SAXS) and Small-angle neutron scattering (SANS) for structural characterization.

Main Results:

• Essential oils exhibited varied insertion and swelling behaviors, indicating diverse interaction mechanisms with Pluronic monomers.
• Oil addition increased micellization enthalpy and decreased the critical micellar temperature (CMT) due to water release.
• SANS revealed large aggregate formation below CMT, with decreasing size above CMT. Combined SAXS/SANS at 37 °C showed partial phase separation in the poly(propylene oxide) core, while the poly(ethylene oxide) shell remained intact.

Conclusions:

• The study highlights distinct oil-Pluronic F127 interactions influencing micellar properties.
• Phase separation within the core at physiological temperature suggests implications for controlled release applications.