Negative electrostatic contribution to the bending rigidity of charged membranes and polyelectrolytes screened by multivalent counterions.
Negative electrostatic contribution to the bending rigidity of charged membranes and polyelectrolytes screened by multivalent counterions.
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DOI：
10.1103/physreve.60.7032
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发表时间：
1999-04
期刊：
影响因子：
--
通讯作者：
T. Nguyen;I. Rouzina;B. Shklovskii
中科院分区：
文献类型：
--
作者：
T. Nguyen;I. Rouzina;B. Shklovskii
已知被单价抗衡离子屏蔽的带电膜或膜的弯曲刚度通过静电效应而增强。我们表明，在屏蔽的情况下，由多价抗衡离子的静电效应降低的弯曲刚度。这种反转的静电贡献的符号是与形成的二维强相关液体（SCL）的抗衡离子在带电的表面，由于它们之间的强大的横向排斥。当膜或膜片弯曲时，SCL在一侧被压缩而在另一侧被拉伸，使得SCL的热力学性质有助于弯曲刚度。SCL的热力学性质与Wigner晶体相似，但SCL的压力、可压缩性和屏蔽半径均为负值。这对弯曲刚度带来了实质性的负校正。就DNA而言，这种效应在性质上与实验一致。
Bending rigidity of a charged membrane or polyelectrolyte screened by monovalent counterions is known to be enhanced by electrostatic effects. We show that in the case of screening by multivalent counterions the electrostatic effects reduce the bending rigidity. This inversion of the sign of the electrostatic contribution is related to the formation of two-dimensional strongly correlated liquids (SCL) of counterions at the charged surface due to strong lateral repulsion between them. When a membrane or a polyelectrolyte is bent, SCL is compressed on one side and stretched on the other so that thermodynamic properties of SCL contribute to the bending rigidity. Thermodynamic properties of SCL are similar to those of Wigner crystal and are anomalous in the sense that the pressure, compressibility and screening radius of SCL are negative. This brings about substantial negative correction to the bending rigidity. For the case of DNA this effect qualitatively agrees with experiment.