Cationic prevesicle and vesicle nanoaggregates: an experimental and theoretical study

Area of Science:

• Colloid and Surface Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Surfactant self-assembly into vesicles is crucial for drug delivery and nanotechnology.
• Understanding mixed surfactant systems provides insights into complex aggregate formation.
• Cationic surfactants are widely used in various industrial and biomedical applications.

Purpose of the Study:

• To investigate the formation and properties of mixed prevesicles and vesicles.
• To explore the influence of different cationic surfactants on aggregate structure and stability.
• To validate theoretical models against experimental observations for mixed surfactant systems.

Main Methods:

• Precise experimental techniques: conductometry, transmission electron microscopy (TEM, cryo-TEM), laser Doppler electrophoresis (LDE), steady-state fluorescence spectroscopy.
• Theoretical models: DLVO theory and its modifications (Inoue's, Sogami's models).
• Development and application of new potentials combining existing theoretical frameworks.

Main Results:

• Confirmed the existence of critical aggregation and vesicle concentrations in dilute solutions.
• Observed unilamellar, spherical vesicles with moderate polydispersity in the postvesicle domain.
• Determined average surface charge densities for pure and mixed vesicles.
• Found hydrophobicities of the bilayer and vesicle surface comparable to specific dielectric constants.

Conclusions:

• Theoretical predictions support the stability of both pure and mixed vesicles.
• The study provides a comprehensive understanding of mixed cationic surfactant vesicle formation.
• Findings contribute to the rational design of self-assembled nanostructures for various applications.