DYNAMICS OF WORMLIKE MICELLES - THE BOND-INTERCHANGE REACTION SCHEME
DYNAMICS OF WORMLIKE MICELLES - THE BOND-INTERCHANGE REACTION SCHEME
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DOI：
10.1021/la00027a015
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发表时间：
1993-03-01
期刊：
影响因子：
3.9
通讯作者：
CATES, ME
中科院分区：
文献类型：
--
作者：
TURNER, MS;MARQUES, C;CATES, ME
我们从理论上研究了发生键交换反应的细长虫状胶束系统的动力学。当两个胶束沿着它们的弧长在某一点上接触时，键交换反应就会发生。一种类似于四臂星形聚合物的瞬态结构被短暂地形成，衰变后产生两个新的胶束，其中第一个胶束的每个部分融合到第二个胶束的一个或另一个部分。首先，我们考虑了虫状胶束系统的分子量分布（MWD）在任意（材料守恒）扰动后的弛豫。我们发现键交换反应并没有为MWD松弛到平衡提供途径。其次，我们考虑了虫状胶束纠缠系统的动力学。我们计算了终端时间、粘度和单体扩散常数与表面活性剂的体积分数的标度，其中胶束反应是快速的时间尺度上的重复。这些结果可能有助于识别发生键交换反应的体系。最后讨论了“管”模型在这些系统中的有效性。考虑到键交换反应允许链相互穿过，我们考虑基于管模型的描述何时是合适的。
We study theoretically the dynamics of systems of elongated wormlike micelles which undergo ''bond-interchange'' reactions. Bond-interchange reactions may occur when two micelles come into contact at some point along their arc lengths. A transient structure resembling a four-armed star polymer is formed briefly, decaying to give two new micelles with each section of the first micelle fusing to one or other section of the second. First we consider the relaxation of the molecular weight distribution (MWD) of a system of wormlike micelles after an arbitrary (material conserving) perturbation to the MWD. We show that bond-interchange reactions do not provide a pathway for the relaxation of the MWD to equilibrium. Second we consider the dynamics of entangled systems of wormlike micelles. We calculate the scaling of the terminal time, viscosity, and monomer diffusion constant with the volume fraction of surfactant in the regime where micellar reactions are rapid on the time scale of reptation. These results may help in identifying systems in which bond-interchange reactions occur. Finally we discuss the validity of the ''tube'' model in these systems. We consider when a description based on the tube model is appropriate, given that bond-interchange reactions allow chains to pass through one another.