“School of Physic”

Back to Papers Home
Back to Papers of School of Physic

Paper   IPM / Physic / 6922
School of Physics
  Title:   Conformational Instability of Rodlike Polyelectrolytes Due to Counterion Fluctuations
1.  R. Golestanian
2.  T. B. Liverpool
  Status:   Published
  Journal: Phys. Rev. E
  No.:  95
  Vol.:  66
  Year:  2002
  Pages:   051802-1-7
  Supported by:  IPM
The effective elasticity of highly charged stiff polyelectrolytes is studied in the presence of counterions, with and without added salt. The rigid polymer conformations may become unstable due to an effective attraction induced by counterion density fluctuations. Instabilities at the longest, or intermediate length scales may signal collapse to globule, or necklace states, respectively. In the presence of added-salt, a generalized electrostatic persistence length is obtained, which has a nontrivial dependence on the Debye screening length. It is also found that the onset of conformational instability is a re-entrant phenomenon as a function of polyelectrolyte length for the unscreened case, and the Debye length or salt concentration for the screened case. This may be relevant in understanding the experimentally observed re-entrant condensation of DNA.

Download TeX format
back to top
scroll left or right