EFFECT OF POLYDISPERSITY ON THE ISOTROPIC-NEMATIC PHASE-TRANSITION OF RIGID RODS
EFFECT OF POLYDISPERSITY ON THE ISOTROPIC-NEMATIC PHASE-TRANSITION OF RIGID RODS
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DOI：
10.1103/physreve.50.2849
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发表时间：
1994-10-01
影响因子：
2.4
通讯作者：
CHEN, ZY
中科院分区：
文献类型：
--
作者：
CHEN, ZY
用二阶微扰理论分析了多分散性对刚性杆各向同性向列型相变的影响，其中任意分数的宽度a作为扰动参数。这些结果表明，各向同性-向列型相变发生在如下条件下：各向同性密度n(I)，其中L(N)(2)棒上的n(I)(1)D=4.189(1+2.128 sigma(2))，向列相密度nh，其中L(N)(2)棒上的n(N)($)D=5.336(1+1.655 sigma(2))，D和L棒(N)上的棒的平均长度和直径。在转变密度下，重和数平均取向序参数值分别为：S-W=0.7922+1.1333西格玛(2)和S-L=0.7922+0.816西格玛(2)；各向同性相棒数平均长度(1)对L棒(I)和向列相棒数平均长度(1)对L棒(N)，比L棒(I)/(1)棒L(N)=1-1.844西格玛(2)。将这些摄动结果与各向同性-向列相转变的平衡条件的数值解进行了比较，这些条件服从两个模拟的数分数分布。
The effect of polydispersity on the isotropic-nematic phase transition of rigid rods is analyzed in terms of a second-order perturbation theory, in which the width a of an arbitrary number fraction is used as a perturbation parameter. These results show that the isotropic-nematic phase transition takes place at the isotropic density n(I), where n(I) ($) over bar L(N)(2)D=4.189(1+2.128 sigma(2)), and the nematic density nh, where n(N) ($) over bar L(N)(2)D=5.336(1+1.655 sigma(2)), with D and ($) over bar L(N) being the diameter and the number-averaged length of rods in the nematic phase. At the transition density, the weight- and number-averaged orientation order parameters have the values S-W=0.7922+1.1333 sigma(2) and S-L=0.7922+0.816 sigma(2); the ratio between the number-averaged length of rods in the isotropic phase, ($) over bar L(I), and that in the nematic phase, ($) over bar L(N), is ($) over bar L(I)/($) over bar L(N)=1-1.844 sigma(2). These perturbation results are compared with the numerical solution of the equilibrium conditions for the isotropic-nematic transition of rods obeying two modeled number fraction distributions.