Surfactant-Mediated Polyelectrolyte Self-Assembly in a Polyelectrolyte- Surfactant Complex

M Goswami and JM Borreguero and PA Pincus and BG Sumpter, MACROMOLECULES, 48, 9050-9059 (2015).

DOI: 10.1021/acs.macromol.5b02145

Self-assembly and dynamics of a polyelectrolyte (PE) surfactant complex (PES) are investigated using molecular dynamics simulations. The complexation is systematically studied for five different PE backbone charge densities. At a fixed surfactant concentration the PES complexation exhibits pearl necklace to agglomerated double spherical structures with a PE chain decorating the surfactant micelles. The counterions do not condense on the complex but are released in the medium with a random distribution. The relaxation dynamics for three different length scales, the polymer chain, segmental, and monomer, show distinct features of the charge and neutral species; the counterions are fastest followed by the PE chain and surfactants. The surfactant heads and tails have the slowest relaxation due to their restricted movement inside the agglomerated structure. At the shortest length scale, all the charge and neutral species show similar relaxation dynamics confirming Rouse behavior at monomer length scales. Overall, the present study highlights the structure property relationship for polymer-surfactant complexation. These results help improve the understanding of PES complexes and should aid in the design of better materials for future applications.

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