Solvent Tunable Self-Assembly of Amphiphilic Rod–Coil Block Copolymers with Chiral, Helical Polycarbodiimide Segments: Polymeric Nanostructures with Variable Shapes and Sizes

Abstract

The nanoscale self-assembly of four amphiphilic rod–coil di- and triblock copolymers with chiral, rodlike poly(N-1-phenethyl-N′-methylcarbodiimide) (PPMC) segments and random coil, hydrophilic PEG blocks has been investigated using dynamic light scattering (DLS) and tapping-mode atomic force microscopy (AFM). This self-assembly proved to be highly tunable simply upon altering the concentration and chemical structure of the hydrophilic selective solvent and/or blending the copolymers with polycarbodiimide homopolymer. When spin-coated from dilute (c = 0.5 mg/mL) THF/H2O solutions, these interesting polymers adopted either simple spherical micelles or spherical polymersomes depending on the relative amount of H2O used for dissolution. Switching selective solvent from H2O to MeOH induced changes in aggregation behavior, as evidenced by DLS and AFM, with interesting nanoworm and nanomaggot micelle assemblies observed when spin-coated from dilute THF/MeOH solutions. Blending high-MW PPMC homopolymer with the b...