Anomalous dynamical light scattering in soft glassy gels
Anomalous dynamical light scattering in soft glassy gels
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DOI：
10.1140/epje/i2002-10075-3
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发表时间：
2002-11-01
影响因子：
1.8
通讯作者：
Pitard, E
中科院分区：
文献类型：
--
作者：
Bouchaud, JP;Pitard, E
我们计算了弹性介质中由于结构的“微坍塌”而在空间和时间上随机出现力偶极子时的动力结构因子S(q，tau)。根据波矢q和崩塌时间θ的不同，发现了不同的状态。在早期的区域中，结构因子的对数表现为(Qtau)(3/2)，如(L.Cipelletti等人，Phys.莱特牧师。84,2275(2000))使用启发式论点。然而，在中间时段，我们更愿意获得(Qtau)(5/4)行为。最后，发现渐近的长时间区表现为Q(3/2)tau。我们还给出了一个合理的老化情景，即微坍塌的应变相关能垒。发现弛豫时间随年龄t(W)呈准指数增长，然后呈对数修正的t(W)(4/5)增长。
We compute the dynamical structure factor S(q, tau) of an elastic medium where force dipoles appear at random in space and in time, due to "micro-collapses" of the structure. Various regimes are found, depending on the wave vector q and the collapse time theta. In an early time regime, the logarithm of the structure factor behaves as (qtau)(3/2), as predicted in (L. Cipelletti et al., Phys. Rev Lett. 84, 2275 (2000)) using heuristic arguments. However, in an intermediate-time regime we rather obtain a (qtau)(5/4) behaviour. Finally, the asymptotic long-time regime is found to behave as q(3/2)tau. We also give a plausible scenario for aging, in terms of a strain-dependent energy barrier for micro-collapses. The relaxation time is found to grow with the age t(w), quasi-exponentially at first, and then as t(w)(4/5) with logarithmic corrections.