Nonlinear rheology of CTAB/NaSal aqueous solutions: finite extensibility of a network of wormlike micelles.
Nonlinear rheology of CTAB/NaSal aqueous solutions: finite extensibility of a network of wormlike micelles.
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DOI：
10.1021/la048292v
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发表时间：
2005-01
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影响因子：
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通讯作者：
Tadashi Inoue;Yoshitaka Inoue;H. Watanabe
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作者：
Tadashi Inoue;Yoshitaka Inoue;H. Watanabe
研究了十六烷基三甲基溴化铵（CTAB）和水杨酸钠（鼻）水溶液的非线性流变性。CTAB的浓度固定在0.1 mol L(-1)，鼻腔的浓度在0.07 ~ 0.4 mol L（-1）之间变化。对于所有测试解，动态模量用具有单一松弛时间tau的麦克斯韦模型来描述。测量了稳态剪切流开始后剪切应力σ和第一次法向应力差N(1)的时间演变。对于低鼻鼻浓度的溶液，当剪切速率大于tau（-1）时，观察到应变硬化，σ和N(1)在一定应变下偏离。对于高鼻鼻浓度的溶液，在tau（-1）和某一临界速率(C)之间观察到与普通纠缠聚合物溶液类似的应力超调，而在> (C)处观察到应变硬化。对于弹性固体，有一个简单的关系，N(1)/sigma = gamma，其中gamma是剪切流施加的应变，适用于应变硬化状态下的所有解。应变硬化是由应变相关剪切模量引起的，考虑到网络链的有限可扩展性，用网络理论很好地描述了应变硬化。日志含义成功确定网络链段大小。因此，在快速流动开始后得到的应力应变关系对表征网络性质是有用的。
The nonlinear rheology of aqueous solutions of cetyltrimethylammonium bromide (CTAB) and sodium salicylate (NaSal) was investigated. The concentration of CTAB was fixed at 0.1 mol L(-1), and the concentration of NaSal was varied from 0.07 to 0.4 mol L(-1). For all test solutions, dynamic moduli were described with the Maxwell model having a single relaxation time, tau. Time evolutions of the shear stress, sigma, and the first normal stress difference, N(1), after inception of the steady shear flow were measured. For solutions having low NaSal concentrations, strain-hardening was observed and sigma and N(1) diverged at a certain strain when the shear rate, , exceeded tau(-1). For solutions with high NaSal concentrations, stress overshoot similar to that of ordinary entangled polymer solutions was observed at between tau(-1) and a certain critical rate, (C), while the strain-hardening was observed at > (C). A simple relationship for elastic solids, N(1)/sigma = gamma with gamma being the strain imposed by shear flow, held for all the solutions in the strain-hardening regime. The strain-hardening was attributable to the strain-dependent shear modulus and well described with the network theory considering the finite extensibility of network strands. The segment size of network strands was successfully determined. Thus, the stress-strain relationship obtained after the inception of fast flows is useful for characterizing the network properties.