Regimes of electrostatic collapse of a highly charged polyelectrolyte in a poor solvent.
We perform extensive molecular dynamics simulations of a highly charged, collapsed, flexible polyelectrolyte chain in a poor solvent for the case when the electrostatic interactions, characterized by the reduced Bjerrum length lB, are strong. We find the existence of several sub-regimes in the dependence of the gyration radius of the chain Rgon lBcharacterized by Rg∼ l. In contrast to a good solvent, the exponent γ for a poor solvent crucially depends on the size and valency of the counterions. To explain the different sub-regimes, we generalize the existing counterion fluctuation theory by including a more complete account of all possible volume interactions in the free energy of the polyelectrolyte chain. We also show that the presence of condensed counterions modifies the effective attraction among the chain monomers and modulates the sign of the second virial coefficient under poor solvent conditions.
The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India. anvym@imsc.res.in and Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai-400094, India.
Anvy Moly
http://orcid.org/0000-0002-7507-4640
AM
Tom
The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India. anvym@imsc.res.in and Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai-400094, India.
Satyavani
S
Vemparala
The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India. anvym@imsc.res.in and Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai-400094, India.
R
R
Rajesh
Department of Mathematics, University of Leicester, Leicester LE1 7RH, UK.
Nikolai V
http://orcid.org/0000-0002-7107-0693
NV
Brilliantov