Tabuteau Hervé, Ramos Laurence, Nakaya-Yaegashi Kaori, Imai Masayuki, Ligoure Christian
Laboratoire des Colloïdes, Verres et Nanomatériaux (UMR CNRS-UMII 5587), cc26, Université Montpellier II, 34 095 Montpellier Cedex 5, France.
Langmuir. 2009 Feb 17;25(4):2467-72. doi: 10.1021/la803304z.
We have investigated the nonlinear rheology of a soft composite transient network made of a solution of surfactant wormlike micelles (WM) in the semidilute regime that are reversibly bridged by telechelic polymers. The samples are well described, in the linear regime, as two Maxwell fluids components blends, characterized by two markedly different characteristic times. The slow mode is mainly related to the transient network of entangled WM, and the fast mode to the network of telechelic chains. In this paper we investigate the nonlinear viscoelasticity and show that the nonlinear behavior reflects as well the behavior of two coupled networks. On one hand, stress relaxation experiments and time-resolved stress response following the application of a constant shear rate show that, in the weakly nonlinear regime, these novel composite networks stiffen. A fourfold increase of the elastic modulus with respect to the linear value is reached for strain amplitude of about 200%. This strain hardening is due to the nonlinear stretching of the telechelic polymer chains. On the other hand, the samples exhibit shear banding in the highly nonlinear regime, similarly to pure semidilute solutions of WM.
我们研究了一种软复合瞬态网络的非线性流变学，该网络由表面活性剂蠕虫状胶束（WM）在半稀溶液状态下形成，并由遥爪聚合物可逆桥接。在线性范围内，样品可以很好地描述为两种麦克斯韦流体组分的混合物，其特征在于两个明显不同的特征时间。慢模式主要与缠结的WM瞬态网络有关，而快模式与遥爪链网络有关。在本文中，我们研究了非线性粘弹性，并表明非线性行为同样反映了两个耦合网络的行为。一方面，应力松弛实验以及在施加恒定剪切速率后的时间分辨应力响应表明，在弱非线性范围内，这些新型复合网络会变硬。对于约200%的应变幅度，弹性模量相对于线性值增加了四倍。这种应变硬化是由于遥爪聚合物链的非线性拉伸。另一方面，与纯WM半稀溶液类似，样品在高度非线性范围内表现出剪切带。
