Critical polyelectrolyte adsorption under confinement: planar slit, cylindrical pore, and spherical cavity.
Critical polyelectrolyte adsorption under confinement: planar slit, cylindrical pore, and spherical cavity.
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DOI：
10.1002/bip.22023
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发表时间：
2012-05
期刊：
影响因子：
2.9
通讯作者：
Andrey G. Cherstvy
中科院分区：
文献类型：
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作者：
Andrey G. Cherstvy
我们探讨了三种基本几何构型下柔性双链在带相反电荷的表面之间的受限空间中的吸附性质。为使临界吸附条件合理化，提出了一种求解高分子密度分布本征函数的绿色函数方程的近似一致有效解的方法。同样的方法在我们最近的研究中实现的“逆”问题的吸附到一个平面上，和外表面的棒状和球形障碍物。对于三个吸附几何形状的研究，理论产生简单的缩放关系的最小表面电荷密度，触发链吸附，作为德拜屏蔽长度和表面曲率的函数。聚电解质的包封是由相互作用的静电吸引力的能量向吸附表面和熵排斥的链挤压到一个薄缝或小腔。在表面介导限制的条件下，相对于圆柱形孔和平面狭缝（在相同的界面表面电荷密度下），需要大得多的聚合物线性电荷密度来吸附带电球形腔内部的电荷。最后简要讨论了可能的生物学意义。
We explore the properties of adsorption of flexible polyelectrolyte chains in confined spaces between the oppositely charged surfaces in three basic geometries. A method of approximate uniformly valid solutions for the Green function equation for the eigenfunctions of polymer density distributions is developed to rationalize the critical adsorption conditions. The same approach was implemented in our recent study for the "inverse" problem of polyelectrolyte adsorption onto a planar surface, and on the outer surface of rod-like and spherical obstacles. For the three adsorption geometries investigated, the theory yields simple scaling relations for the minimal surface charge density that triggers the chain adsorption, as a function of the Debye screening length and surface curvature. The encapsulation of polyelectrolytes is governed by interplay of the electrostatic attraction energy toward the adsorbing surface and entropic repulsion of the chain squeezed into a thin slit or small cavities. Under the conditions of surface-mediated confinement, substantially larger polymer linear charge densities are required to adsorb a polyelectrolyte inside a charged spherical cavity, relative to a cylindrical pore and to a planar slit (at the same interfacial surface charge density). Possible biological implications are discussed briefly in the end.