Inorganic-Salt-Induced Morphological Transformation of Semicrystalline Micelles of PCL-b-PEO Block Copolymer in Aqueous Solution

The effect of inorganic salt at concentrations typical of a biological environment on the micellar morphology of semicrystalline PCL-b-PEO in aqueous solution is investigated. The salt is introduced either by dialysis of a THF solution against an aqueous solution of the salt or by adding it into an aqueous solution containing preformed micelles. The inorganic salt can induce sphere-to-rod or sphere-to-lamella transformations of the PCL-b-PEO micelles in aqueous solution, depending on the length of the PCL block. The inorganic salt induces "salting-out" of the PEO block, leading to a decrease in the reduced tethering density of the corona in the micelles.