Structure of Amphiphilic Terpolymer Raspberry Vesicles

Area of Science:

• Polymer Chemistry
• Materials Science
• Computational Chemistry

Background:

• Terpolymer raspberry vesicles possess domains with varying chemical affinities, making them promising for multi-compartment cargo delivery.
• The efficiency of these vesicles as carriers is contingent upon their structural stability and capacity for holding cargo.

Purpose of the Study:

• To investigate the impact of polymer concentration and pairwise interaction energy on the equilibrium aggregate structures of star terpolymers in aqueous solutions.
• To understand the factors governing the transition from micellar to vesicular structures.
• To assess and optimize the solvent encapsulation and release properties of terpolymer vesicles.

Main Methods:

• Dissipative Particle Dynamics (DPD) simulations were utilized to model a star terpolymer system in an aqueous environment.
• Calculations of the free energy for equilibrium aggregates were performed.
• The influence of polymer concentration and pairwise interaction energies on vesicle formation and solvent encapsulation was analyzed.

Main Results:

• A critical polymer concentration threshold was identified as necessary for the formation of vesicles.
• The transition from micelles to vesicles is primarily dictated by the interactions between the longest solvophobic block and the solvent.
• Reduced interaction energy enhances solvent encapsulation, while low repulsive monomer interactions allow for solvent permeation through the vesicle shell.

Conclusions:

• The loading capacity and release kinetics of terpolymer vesicles can be fine-tuned by manipulating the pairwise interaction energies between the polymer and solvent.
• Predicting and controlling these properties are vital for the rational design of vesicles for targeted applications, such as drug delivery.