Persistent Length of a Polyelectrolyte Chain
Abstract
We footnote Work done in collaboration with Namkyoung Lee (University of Florida) present a first principles calculation for the persistence length of a strongly charged linear chain in the presence of ions of salt. Using a perturbation expansion, we calculate the change in the electrostatic potential and ion concentration in the vicinity of a bent homogeneously charged cylinder and the energy needed for its deformation. Depending on the cylinder charge density the persistence length is proportional to Rd or has R_d^2 dependence, where Rd is the Debye screening length in the bulk. This result can be explained by enhanced screening effects due to the high concentration of ions in the vicinity of a chain. We have shown that for strongly charged chain the interaction energy between two test charges placed along the chain decays as 1/r^3. If one of the test charges is on the chain and another is placed distance r in the perpendicular direction, the interaction decays as 1/r^2 (if r is less than Debye length in the bulk).
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 1996
- Bibcode:
- 1996APS..MAR.N3006O