Charge-controlled nano-structuring in partially collapsed star-shaped macromolecules
Résumé
Hydrophobic polyelectrolytes exhibit intra-molecular nano-scale self-organization instead of macroscopic phase separation because of the interplay between short-range hydrophobic attraction and long-range electrostatic repulsion. We aim to unravel how the morphology of the intra-molecular nanostructures can be controlled through the topology of the macromolecule on one hand and by adjustable ionization on the other hand. Specifically, we focus on hydrophobic star-branched polyelectrolytes, composed of either strong or weak acidic monomers. While both collapse in a globule when uncharged, and expand to full stretching of arms at high ionization, they exhibit quite different intermediate scenarios. For the strong ones, we observe the formation of bundles of arms as the main structural motif, and for the weak ones the intramolecular micelle-like structure is found at the same overall charge of the macromolecule. Here intramolecular disproportionation leaves some arms in a collapsed virtually neutral core, while others are substantially ionized and stretched in the corona. © The Royal Society of Chemistry 2016.
Mots clés
Disproportionations
Electrostatic repulsion
Hydrophobic attraction
Hydrophobicity
Hydrophobic polyelectrolytes
Ionization
Macromolecules
Macroscopic phase separation
Micelle-like structures
Molecular nanostructures
Molecular Structure
Nanostructures
Nanotechnology
Phase separation
Polyelectrolytes
Self organizations
Stars