Core-Shell-Corona Micelles from a Polyether-Based Triblock Terpolymer: Investigation of the pH-Dependent Micellar Structure.

Core-shell-corona micelles featuring a pH-responsive shell have been characterized in dilute aqueous solution at different pH values (4-8) by using dynamic light scattering (DLS), field-flow fractionation coupled with multiangle light scattering detector (FFF-MALS), steady-state fluorescence, small-angle X-ray scattering (SAXS), and cryogenic transmission electron microscopy (cryo-TEM). The micelles are formed by self-assembly of a polyether-based triblock terpolymer consisting of a hydrophobic poly( tert-butyl glycidyl ether) block (P tBGE), a pH-responsive modified poly(allyl glycidyl ether) segment (PAGECOOH), and a neutral hydrophilic poly(ethylene oxide) block (PEO). Because of the side-chain carboxylic acids in the middle block, the micellar structure and size depends on the solution pH. Hereby, we show that an increase in pH induces a decrease in the aggregation number ( Nagg). In addition, the combination of the above measurements revealed an unexpected morphological change from spherical to ellipsoidal micelles by increasing pH.