Multicompartment nanoparticles formed by a heparin-mimicking block terpolymer in aqueous solutions

A new amphiphilic block terpolymer poly((sulfamate-carboxylate)isoprene)- block-polystyrene-block-poly (ethylene oxide), PISC₂₃₀-PS ₅₂-PE0₁₅₁, with a narrow molecular weight distribution (PDI = 1.05), was synthesized via the post polymerization reaction of the anionically prepared precursor block terpolymer polyisoprene-block-polystyrene- block-poly(ethylene oxide) with chlorosulfonyl isocyanate. The formation and structure of self-assemblies of the polyelectrolyte block terpolymer in dilute aqueous solutions were studied by static and dynamic light scattering, atomic force and cryogenic transmission electron microscopy, fluorometry, and H NMR spectroscopy. In acidic solutions, the terpolymers self-assemble into kinetically trapped multicompartment micelles, with the core consisting of discrete PS and PISC domains and PEO in the shell. If the solution pH is adjusted to the alkaline region, the multicompartment micelles undergo an irreversible transition to regular micelles, with a PS core and a mixed shell formed by PEO and PISC blocks.