Viscoelastic Relaxation Behavior of Polyelectrolyte Complexes from Coacervate to Precipitate

POSTER

Abstract

The relaxation dynamics of polyelectrolyte complexes slows down while transitioning from coacervate to precipitate upon decreasing salt concentration. However, knowledge of such changes over full relaxation spectrum is still limited. This presentation will describe the relaxation behavior of complexes probed over a wide timescale by measuring viscoelastic spectra and zero-shear viscosities at varying temperatures, salt concentrations and molecular weights using a set of model polyelectrolytes. Our studies show that the complexes exhibit time-temperature superposition (TTS) at all salt concentrations, while the range of overlapped-frequencies for time-temperature-salt superposition (TTSS) strongly depends on the salt concentration and gradually shifts to higher frequencies as the complex approaches precipitate phase. Further understanding of this transition using the sticky Rouse model and simulations studies will be presented.

Presenters

  • Samim Ali

    National Institute of Standards and Technology

Authors

  • Samim Ali

    National Institute of Standards and Technology

  • Anand Rahalkar

    National Institute of Standards and Technology

  • Juan De Pablo

    University of Chicago, Chemical Eng., University of Chicago, The Institute for Molecular Engineering, The University of Chicago, Institute for Molecular Engineering, University of Chicago, Institute for Molecular Engineering, The University of Chicago, Institute for Molecular Engineering, Argonne National Laboratory

  • Vivek Prabhu

    National Institute of Standards and Technology, Materials Science and Engineering Division, National Institute of Standards and Technology