Impact of cross-linking on the structural and interfacial properties of surfactant micelles

Structural properties of self-assembled formulations composed of Tyloxapol and Triton X-100 surfactants were investigated using all-atomic molecular dynamics simulations. Tyloxapol is a polymerized version of the Triton X-100 non-ionic surfactant. Multiple systems were investigated and compared – pure Tyloxapol or Triton X-100 systems and mixed systems containing different concentrations of the two surfactants. We find that crosslinking of monomers greatly affects the overall structure and stability of the resulting micellar structure. Structural analysis shows that pure tyloxapol systems are relatively spherical in shape and become more aspherical by replacing tyloxapol molecules with a corresponding number of Triton X-100 monomers. Interestingly, the initial analysis shows the most stable of the mixed systems has a 50:50 ratio of Tyloxapol and Triton X-100. Finally, a novel method was developed to calculate volumes of the micelles as well as the intrinsic density profiles of the different species regardless of the nanoparticle's shape.