ELECTRIC PROPERTIES OF MACROMOLECULES .5. THEORY OF IONIC POLARIZATION IN POLYELECTROLYTES
ELECTRIC PROPERTIES OF MACROMOLECULES .5. THEORY OF IONIC POLARIZATION IN POLYELECTROLYTES
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DOI：
10.1021/j100834a023
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发表时间：
1960-01-01
影响因子：
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通讯作者：
OKONSKI, CT
中科院分区：
文献类型：
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作者：
OKONSKI, CT
离子输运现象被证明是重要的介电常数，以及分散性和导电性的polvelectrolyte溶液。界面处离子的迁移率引起的过剩电导率的影响，以及在薄离子气氛下由于抗衡离子引起的电荷输运，可以用二维电导率来表示。电边值问题是制定在这个表面电导率，介质的介电常数和体积电导率，和各向异性的介电常数和体积电导率的颗粒。这些参数对大分子结构具有重要的物理意义。有人建议，该模型是更适合于聚电解质比Debye-Falkenhagen或麦克斯韦-瓦格纳模型。各向同性球被认为是详细的，以显示的影响，表面电导率的内场，激发极化，和介电常数，色散，和电导率的稀释系统。找到了合理的近似，详细地处理了广义椭球的边值问题和圆柱的极限形式。均匀表面电导率的各向异性粒子与各向异性体积电导率的粒子在电学上是等效的。本文给出了椭球粒子稀体系的复介电常数、弛豫时间、低频和高频介电增量和电导率增量的计算公式。数值计算的增量作出了随机和完全取向的椭球体的旋转在广泛的参数范围内适当稀释水介质。在各向异性粒子的取向系统中，除了聚离子摩擦系数各向异性的贡献外，对流输运还产生低频介电增量的各向异性和电导率的各向异性。此外，内部场取决于取向，并且这种对聚离子迁移率的影响可能大大超过Eigen和施瓦茨讨论的摩擦系数效应。结果表明，基本上所有已知的介电性质的含水蛋白质，核酸，核蛋白质，带电胶体是解释在这个模型。结果表明，反离子大气的极化降低了内部场，从而减少了永久偶极极化。现有的实验数据，一般不完整的本解释，讨论尽可能。需要进一步的实验来测试的理论表示，并提出了一些关键的。据预测，在强高频场的生物效应可以通过使用脉冲辐射增强。
Ionic transport phenomena are shown to be important to the dielectric constant, as well as the dispersion and conductivity of polvelectrolyte solutions. The effects of the excess conductivity arising from mobility of ions at the interface, and—with thin ion atmospheres—thecharge transport due to counterions, may be expressed in terms of a two-dimensional conductivity. The electrical boundary value problem is formulated in terms of this surface conductivity, the dielectric constant and volume conductivity of the medium, and an anisotropic dielectric constant and volume conductivity for the particle. These param-eters have important physical significance for macromolecular structures. It is proposed that this model is more appropriate for polyelectrolytes than either the Debye-Falkenhagen or Maxwell-Wagner models. Isotropic spheres are considered in detail, toshow the effects of a surface conductivity on the internal field, the induced polarization, and the dielectric constant, dispersion, and conductivity of dilute systems. Reasonable approximations were found which obviate detailed treatment of the boundary-value problems for the generalized ellipsoid and the limiting forms of a cylinder. Anlsometric particles of uniform surface conductivity are shown to be electrically equivalent to particles of anisotropic volume conductiv-ity. Equations are given for the complex dielectric constant, the relaxation times, and the low and high frequency dielec-tric and conductivity increments of dilute systems of ellipsoidal particles. Numerical calculations of the increments are made forrandomly and completely oriented ellipsoids ofrevolution over a wide range of parameters appropriate todilute aqueous media. Important differences between needle and disk-shaped particles are found. In oriented systems of aniso-metric particles, counterion transport produces a strong anisotropy of the low frequency dielectric increment, and an aniso-tropy of conductivity apart from the contribution due toanisotropy of the frictional coefficient of the polyion. Further, the internal field depends upon orientation, and this effect on polyion mobility may greatly exceed the frictional coefficient effect discussed by Eigen and Schwarz. The results indicate that essentially all of the known dielectric properties of aqueous proteins, nucleicacids, nucleoproteins, and charged colloids are explicable in terms of this model. It is shown that polariza-tion of the counterion atmosphere reduces theinternal field and thus diminishes permanent dipole polarization. Available experimental data, generally incomplete for the present interpretation, are discussed in as far as possible. The need for further experiments to test the theory is indicated, and some crucial ones are suggested. It is predicted that biological effects in intense high frequency fields may be enhanced by the use of pulsed radiation.