Effect of polyelectrolyte mixing ratio and hydrophobic interactions on dynamics of (HM-)PDMAEMA/PEO-PMAA complexes

The complexation of oppositely charged polyelectrolytes leads to Polyelectrolyte Complexes (PECs). PECs can exist in many different states, depending on the architecture of the polymers and the environmental parameters of the solution. Using double hydrophilic block copolymers (DHBCs), PECs can be stabilized as dispersed aggregates in solutions. Specifically, the polymers involved in this investigation are a DHBC composed of a poly(ethylene glycol) block and a poly(methacrylic acid) block (PEO-PMAA) used as the polyanion and poly(2-(dimethylamino)ethyl methacrylate), with and without hydrophobic dodecyl substitutions, used as the polycation. In this paper, we discuss the behavior of the nanoscale dynamics with respect to their mixing ratio. We also test the impact of hydrophobic modifications on the dynamics of the aggregates. By neutron spin echo spectroscopy and neutron backscattering spectroscopy, we observed the role of electrostatic interaction as a friction induced on the polymers, where complexation leads to slower diffusion and the hydrophobic moieties affect the rigidity of the polymers.