2017 Annual Meeting
(689d) Self Consistent Field Theory Study of Multivalent Cation Effect on Semiflexible End-Grafted Random Polyelectrolytes
Authors
This theoretical study implements a Self Consistent Field Theory (SCFT) approach to build the molecular model for the random polyelectrolytes grafted to a surface and surrounded by multivalent cations. Structural rigidity of the polyelectrolyte chain is taken into account by using the Wormlike Chain Model of semi-flexible polymers. The molecular model properly accounts for the structural, thermodynamic and electrostatic properties of all the species present in the system. The highly non-additive coupling between various interactions creates a varying local environment near each polyelectrolyte chains that ultimately results in collapse of the chain. Formation of salt bridge between different chains with the aid of multivalent cations is considered in this theory by using a chemical reaction formalism. Poor solvent quality due to presence of thermodynamically controlled salting out effect is accounted with a Flory-Huggins Chi parameter . Variation of the cation effect is analyzed at different pH, salt concentration, polymer grafting density and polymer chain length. This model gives an exhaustive framework to demonstrate multivalent cation induced structural change in random polyelectrolytes tethered to nano surfaces for drug delivery and biosensing applications and also in colloid chemistry.
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References
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