Materials Science & Engineering
North Carolina State University
Molecular modeling of structure and salt-responsive morphology of polyelectrolyte-based materials
Location: EB1 Room 1011
Friday, October 9th 2015 - 11:00 am
Polyelectrolyte block copolymers, which combine structural features of polyelectrolyte, block copolymers and surfactants, can self-assemble in a variety of nanoaggregates in aqueous environment, such as micelles, vesicles, lamellar mesophases or micellar aggregates. The morphology and size of formed aggregates are determined by the characteristically complex equilibrium of noncovalent forces (electrostatic, steric, hydrogen bonding, Van der Waals, and hydrophobic interactions) and depends on variations in ionic strength or/and pH in the aqueous solution. Due to responsive nature of these materials their properties and morphology are difficult to predict.
We have recently developed a new methodology for the Dissipative Particle Dynamics simulation method which permits large-scale simulation of self-assembling polyelectrolytes and their response to the changes in salt concentration. In this talk, I will illustrate our recent progress in prediction of responsive morphologies of polyelectrolytes on the example of the DNA-based materials. Specifically, I will first discuss determination of the persistence length of ssDNA using atomistic molecular dynamics simulations and then the prediction of the solvent and length dependent self-assembly of polyelectrolyte block copolymers into various morphologies. Our methodology permit us to construct a morphological diagram of polyelectrolyte block copolymers and evaluate the size of aggregates obtained along with their responsive morphological transitions and scaling relation. Our results show that our method can be used as a powerful tool to guide the rational design of solvent-responsive polyelectrolyte-based nanostructures.