Flow-induced phase transitions in rod-like micelles
Flow-induced phase transitions in rod-like micelles
复制标题
棒状胶束中流动诱导的相变
DOI：
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
M. Cates
中科院分区：
文献类型：
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作者：
M. S. Turner;M. Cates
作者研究了自组装棒状胶束在剪切流和拉伸流下的动力学。他们假设了一个简单的反应方案，其中两个胶束只有在共线时才能融合。这导致胶束排列和生长之间的正反馈机制。他们将 tau 蛋白断裂定义为典型胶束的反应时间，将 tau 蛋白旋转定义为其旋转扩散时间。他们考虑了 tau 断裂 > tau 腐烂的极限情况。通过匹配这些限制结果，他们能够对一般情况做出一些预测。在拉伸流动中，他们预测在某些临界流速下，凝胶转变为与流动轴完全对齐的极长棒的阶段。结果表明，这些棒的长度可以远大于不存在流动时的平均胶束长度，但相对于流动中产生的张力仍然稳定。研究发现，尽管流动轴附近的平均胶束尺寸仍预计在高流速下急剧增加，但剪切流中不存在类似的转变。作者简要讨论了计算与胶束系统中剪切诱导结构实验的相关性。
The authors study the dynamics of self-assembling rod-like micelles under both shear and elongational flow. They assume a simple reaction scheme in which two micelles can fuse only if they are collinear. This results in a positive feedback mechanism between micellar alignment and growth. They define tau break as the reaction time for a typical micelle and tau rot as its rotational diffusion time. They consider both the limiting case of tau break > tau rot. By matching these limiting results they are able to make some predictions for the general case. In elongational flow they predict a gelation transition, at some critical flow rate, to a phase of extremely long rods which are fully aligned with the flow axis. It is shown that these rods can be of a length which is very much greater than the mean micellar length in the absence of flow but which is still stable with respect to the tension produced in a flow. It is found that the analogous transition in shear flow is absent although the mean micellar size near the flow axis is still expected to increase sharply at high flow rates. The authors briefly discuss the relevance of the calculations to experiments on shear-induced structures in micellar systems.