Thermodynamics, Microstructures, and Solubilization of Block Copolymer Micelles by Density Functional Theory

Block copolymer micelle is one of the most versatile self-assembled structures with applications in drug delivery, cosmetic products, and micellar-enhanced ultrafiltration. The key to design an effective block copolymer to form micelles is to understand how molecular architecture affects critical micelle concentrations, micellar dimensions, and partitioning of solute into the micelle. In this work, we studied micelles from nonionic block copolymers using interfacial statistical associating fluid theory a density functional theory, which explicitly includes block copolymer-water hydrogen bonding and water-water hydrogen bonding. We are able to predict and explain how micellar thermodynamic properties depend on polymer chain architecture. Dimension and aggregation of micelles are investigated for block copolymers with different hyrophobes and hydrophiles. The effects of temperature and pressure on micelle stability are also captured by the theory. The enhanced solubility of hydrophobic substance in water by micelle loading is demonstrated, and predicted solute distribution answers the question about the locus of benzene in micelles from a theoretical perspective.