Single-particle Brownian dynamics for characterizing the rheology of fluid Langmuir monolayers
Single-particle Brownian dynamics for characterizing the rheology of fluid Langmuir monolayers
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DOI：
10.1209/0295-5075/79/66005
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发表时间：
2007-09
期刊：
影响因子：
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通讯作者：
M. Sickert;F. Rondelez;Howard A. Stone
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文献类型：
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作者：
M. Sickert;F. Rondelez;Howard A. Stone
亚微米直径球体的布朗运动已用于研究低密度极限（液体膨胀相）下短链表面活性剂的朗缪尔单分子层的流变学。我们展示了如何通过使用尺寸远大于单层厚度的球体的最新理论模型，从先前测量的扩散系数（Sickert M. 和 Rondelez F., Phys. Rev. Lett. 90 (2003) 126104）导出剪切粘度。我们将表面粘度报告为占据表面分数的函数，我们认为这是基于物理一致的实验和理论的第一个此类估计。这两个模型在液体膨胀相的整个表面密度范围内产生表面粘度值 1–5×10−10 Ns/m 和 2–8×10−10 Ns/m。
The Brownian movement of a submicron diameter sphere has been used to study the rheology of Langmuir monolayers of short-chain surfactants in the low-density limit (liquid-expanded phase). We show how the shear viscosity can be derived from previously measured diffusion coefficients (Sickert M. and Rondelez F., Phys. Rev. Lett. 90 (2003) 126104) by using recent theoretical models for a sphere of size much larger than the monolayer thickness. We report the surface viscosity as a function of the occupied surface fraction, which we believe are the first such estimates based on physically consistent experiments and theory. The two models yield values of the surface viscosity 1–5×10−10 Ns/m and 2–8×10−10 Ns/m over the entire range of surface densities of the liquid-expanded phase.