Strong and Weak Polyelectrolyte Adsorption onto Oppositely Charged Curved Surfaces
Strong and Weak Polyelectrolyte Adsorption onto Oppositely Charged Curved Surfaces
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DOI：
10.1007/12_2012_183
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
R. Winkler;Andrey G. Cherstvy
中科院分区：
文献类型：
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作者：
R. Winkler;Andrey G. Cherstvy
聚电解质是由带电单体组成的大分子，由于其柔韧性和静电相互作用的相互作用而表现出独特的性能。在溶液中，它们被吸引到带相反电荷的表面和界面，并在满足有关聚合物和表面的电荷密度以及溶液性质的某些条件时表现出向吸附状态的转变。在这篇综述中，我们讨论了柔性聚电解质在曲面上吸附的两种限制情况：弱吸附和强吸附。在第一种情况下，吸附受到柔性聚电解质的熵自由度的强烈影响。相比之下，在强吸附极限下，静电相互作用占主导地位，这导致特定的吸附模式，特别是在球形表面上。我们讨论了相应的理论方法，应用聚合物的平均场描述和聚合物-表面相互作用。对于弱吸附，我们通过平面和球形几何形状的精确可解模型以及通用近似方案讨论了关键吸附行为，该方案还应用于圆柱表面。为了实现强吸附，我们研究了圆柱体和球体上的各种聚电解质图案并评估了它们的稳定性。根据实验结果（主要是 DNA 吸附实验）对结果进行了讨论。
Polyelectrolytes are macromolecules composed of charged monomers and exhibit unique properties due to the interplay of their flexibility and electrostatic interactions. In solution, they are attracted to oppositely charged surfaces and interfaces and exhibit a transition to an adsorbed state when certain conditions are met concerning the charge densities of the polymer and surface and the properties of the solution. In this review, we discuss two limiting cases for adsorption of flexible polyelectrolytes on curved surfaces: weak and strong adsorption. In the first case, adsorption is strongly influenced by the entropic degrees of freedom of a flexible polyelectrolyte. By contrast, in the strong adsorption limit, electrostatic interactions dominate, which leads to particular adsorption patterns, specifically on spherical surfaces. We discuss the corresponding theoretical approaches, applying a mean-field description for the polymer and the polymer–surface interaction. For weak adsorption, we discuss the critical adsorption behavior by exactly solvable models for planar and spherical geometries and a generic approximation scheme, which is additionally applied to cylindrical surfaces. For strong adsorption, we investigate various polyelectrolyte patterns on cylinders and spheres and evaluate their stability. The results are discussed in the light of experimental results, mostly of DNA adsorption experiments.