Co-Micellization Behavior in Poloxamers: Dissipative Particle Dynamics Study

Abstract

Dissipative particle dynamics simulations are applied to investigate co-micellization behavior for binary mixtures of Poloxamers in dilute aqueous solution. In view of block length similarity/dissimilarity, four representative mixture cases are considered: F127/P123, F127/P105, P123/P84, and F127/L64. With appropriate interaction parameters, the simulations enable us to examine the formation of micelles, their types, size, shape, and composition. In the investigated concentration range, we find that pure and mixed micelles, both ellipsoidal, always coexist for all cases. At similar concentrations, both species form pure micelles of their own together with mixed micelles. In the case of F127/L64, it is found that the L64 chains are involved in the mixed micelles, even when the L64 concentration is below its CMC. The fraction of L64 involved in the mixed micelles is lower as compared to the other systems studied. For all cases, the proportion of mixed micelles can be increased when the two polymer species have similar concentrations. Moreover, shorter chains may prefer to straddle the core and corona in the region of ellipsoidal interface that is closer to the center of mixed micelle.

Kinetics of Chain Exchange between Diblock Copolymer Micelles

“…DPD is a mesoscale simulation method developed by Hoogerbrugge and Koelman . It is commonly used to study complex fluids including the self‐assembly behavior of amphiphilic block copolymers . Briefly, this simulation is based on Newton's 2nd law of motion.…”

“…The simulations are carried out using LAMMPS by adopting a NVT ensemble. Further details about methodology has been described in our previous work …”

“…[ 30 ] It is commonly used to study complex fl uids including the self-assembly behavior of amphiphilic block copolymers. [ 26,31,32 ] Briefl y, this simulation is based on Newton's 2nd law of motion. All beads are assumed to have an identical mass m .…”

Mesoscopic simulation studies on the formation mechanism of drug loaded polymeric micelles

“…Although polymeric micelles as drug carriers have been extensively investigated, it is still highly demanded to make an in-depth and thorough understanding of the complex morphological change of drug loaded polymeric micelles. Depending on block copolymer composition, ionizable blocks, interaction parameter between the blocks, solvent quality, temperature and pH, not only spherical micelles but also bilayers, rods, cylinders and vesicles can be formed [8,9]. Therefore, it is important to investigate the micelle formation mechanism research of drug carriers, which can assist us to understand the morphological structure changes of drug carriers from a microscopic perspective.…”

“…The DPD method is able to intuitively illustrate the formation and morphologies of polymeric micelles and the change of their internal structure [8,28,29]. We may have a better understanding of the formation mechanism of the advanced polymeric carriers according to the analysis of the simulation results.…”