| 초록 |
Complex coacervates (CC) are polymer-rich phase of liquid-liquid phase separation occurring when two oppositely charged polyelectrolytes are mixed in aqueous solutions. Previously, dynamics of CC has been mostly studied by rheology, probing relaxation times on multiple length scales such as reptation, entanglement and ion-pair exchange. However, there are still limited information on the dynamics on monomeric length scale of CC. In this study, the segmental dynamics of CC are revealed as a function of salt concentration by quasi-elastic neutron scattering. Model polyelectrolytes functionalized with ammonium, guanidinium and sulfonate groups were synthesized by anionic ring-opening polymerization and post-modification. As the salt concentration increases, the amount of unpaired segments in ammonium-based coacervates increases, resulting in enhanced segmental relaxation. In contrast, guanidinium-based coacervates show slow segmental dynamics independent on the salt concentration. |
