Rheological properties of wormlike micelles formed in concentrated region of nonionic surfactant (C16E7)-water system
Rheological properties of wormlike micelles formed in concentrated region of nonionic surfactant (C16E7)-water system
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非离子表面活性剂(C16E7)-水体系集中区域形成的蠕虫状胶束的流变特性
DOI：
10.1007/s00396-015-3776-4
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
and T. Kato
中科院分区：
文献类型：
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作者：
Y. Shimada;Y. Kawabata;and T. Kato
本文研究了七甘醇正十六烷基醚（C16 E7）/D_2O体系浓胶束溶液（最高达40wt%）的流变性。由粘弹谱G ′和G ″的频率依赖性得到应力松弛时间τ和平台模量G∞，由稳态剪切粘度的剪切速率依赖性得到零剪切粘度η0。双对数曲线的斜率G ∞vs.浓度几乎与温度无关，而τ随温度的升高而急剧下降，在40 °C时变为负值。η 0的斜率也随着温度的升高而急剧减小，并且在约50 °C以上几乎变为常数。在较高温度下的这些极限值与Hoffmann（ACS Symp Ser 578：2-31（1994））的简单模型预测的理论值很好地一致，其中考虑了幽灵状交叉和/或滑动连接的应力松弛。还与Tanaka的最新理论（Langmuir 26：5374（2010））进行了比较。本结果证实了Kato等人的自扩散研究的结论（Langmuir 11：4661（1995））;蠕虫状胶束之间的交联在高于约45 °C时开始形成，并且在高于约55 °C时形成几乎饱和的网络。
Rheological measurements have been made in concentrated micellar solutions (up to 40 wt%) of heptaethylene glycoln-hexadecyl ether (C16E7)/D2O system. The stress relaxation time (τ) and the plateau modulus (G∞) have been obtained from the frequency dependences ofG′ andG″(viscoelastic spectra), and the zero-shear viscosity (η0) has been obtained from the shear rate dependence of the steady shear viscosity. The slope of the double logarithmic plot ofG∞vs. concentration is almost independent of temperature whereas that ofτsteeply decreases with increasing temperature and becomes negative at 40 °C. The slope forη0also steeply decreases with increasing temperature and becomes almost constant above about 50 °C. These limiting values at higher temperatures are in good agreement with the theoretical values predicted by a simple model of Hoffmann (ACS Symp Ser 578:2–31 (1994)) where the ghost-like crossing and/or sliding connections are taken into account for the stress relaxation. Comparison with the recent theory of Tanaka (Langmuir 26:5374 (2010)) has also been made. The present results confirm the conclusion of the self-diffusion study of Kato et al. (Langmuir 11:4661 (1995)); the crosslinking between wormlike micelles begins to form above about 45 °C, and almost saturated networks are formed above about 55 °C.