Bilayer membrane in confined geometry: Interlayer slide and entropic repulsion
Bilayer membrane in confined geometry: Interlayer slide and entropic repulsion
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DOI：
10.1134/1.1826180
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发表时间：
2004-01-01
影响因子：
1.1
通讯作者：
Mukhin, SI
中科院分区：
文献类型：
--
作者：
Baoukina, SV;Mukhin, SI
从弹性理论的第一性原理出发，导出了双层类脂膜的自由能泛函。该模型明确地包括位置相关的单分子层的相互滑动和弯曲变形。我们的自由能功能的液晶膜允许膜的不可压缩性和消失的面内剪切模量和服从反射和旋转对称性的平面双层。膜中平面的层间滑动导致单分子膜表面密度的局部差异。滑动振幅通过应变张量直接进入自由能。对于小的弯曲变形，弯曲模量与面积压缩系数之间的比率K-b/K-A与单层厚度h的平方成比例。利用该泛函，我们对作用在距离为2d的平行限制壁之间的双层上的熵势进行了自洽计算。我们发现，在最小限制势下，与T-2/K（B）d（4）成正比的温度相关曲率α，对于带滑动的双层膜比单位双层膜提高了4倍。我们还计算了双层膜之间的限制壁的粘性模式。纯弯曲的膜进行了研究，这是解耦的面积膨胀在小幅度。粘性耗散的三个来源被认为是：水和膜的粘度和层间阻力。色散关系给出两个分支Ω（1，2）（q）。(C)2004年MAIK“Nauka /Intertina”。
We derive the free energy functional of a bilayer lipid membrane from the first principles of elasticity theory. The model explicitly includes position-dependent mutual slide of monolayers and bending deformation. Our free energy functional of a liquid-crystal membrane allows for incompressibility of the membrane and vanishing of the in-plane shear modulus and obeys reflectional and rotational symmetries of the flat bilayer. Interlayer slide at the midplane of the membrane results in local difference of surface densities of the monolayers. The slide amplitude directly enters the free energy via the strain tensor. For small bending deformations, the ratio between the bending modulus and the area compression coefficient, K-b/K-A , is proportional to the square of monolayer thickness h. Using the functional, we perform self-consistent calculation of the entropic potential acting on a bilayer between parallel confining walls separated by distance 2d. We find that at the minimum of the confining potential, the temperature-dependent curvature alpha proportional to T-2/K(b)d(4) is enhanced four times for a bilayer with slide as compared with a unit bilayer. We also calculate viscous modes of a bilayer membrane between confining walls. Pure bending of the membrane is investigated, which is decoupled from area dilation at small amplitudes. Three sources of viscous dissipation are considered: water and membrane viscosities and interlayer drag. The dispersion relation gives two branches omega(1, 2)(q). (C) 2004 MAIK "Nauka / Interperiodica".