Overcoming limitations of conventional solvent exchange methods: Achieving monodisperse non-equilibrium polymer micelles through equilibration-nanoprecipitation (ENP)

Hypothesis Conventional solvent exchange formulation methods face limitations when trying to control the final equilibrium size properties of block copolymer micelles containing a strongly hydrophobicity and a block because the solvent conditions are not well controlled during micelle formation. Therefore, using alternative formulation method, named Equilibration-Nanoprecipitation (ENP), in which micelles are formed under uniform solvent conditions, will significantly reduce the final dispersity compared a conventional solvent exchange method. Experimental: Size properties of the final aqueous micelle dispersions formed from the ENP method and a ventional solvent exchange are measured using DLS. Also, a parallel modelling study is completed to predict final size distributions using both methods. Findings The experimental results demonstrate the ENP method is effective producing non -equilibrium micelles with dispersity below the monodisperse polydispersity index (PDI) cutoff for DLS while the conventional solvent exchange method leads to significantly greater dispersity. Also the experimental results highlight ENP can used to tune the final size properties which cannot be done using methods which do not properly control micelle formation conditions. Additionally, the modelling study supports the utility of the ENP approach for producing monodisperse dispersions of nonequilibrium polymer micelles.