Dynamics of a colloid-stabilized cream.
Dynamics of a colloid-stabilized cream.
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DOI：
10.1103/physreve.79.011405
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发表时间：
2008-12
期刊：
影响因子：
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通讯作者：
Eva M. Herzig;Aymeric Robert;Aymeric Robert;D. D. V. ’. Zand-D.;Luca Cipelletti;P. Pusey;Paul S. Clegg
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文献类型：
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作者：
Eva M. Herzig;Aymeric Robert;Aymeric Robert;D. D. V. ’. Zand-D.;Luca Cipelletti;P. Pusey;Paul S. Clegg
我们使用x射线光子相关光谱研究了高体积分数乳状液在重力作用下的动力学。十二烷水乳状液具有仅由胶体颗粒(二氧化硅)稳定的界面。样品在混合后不久就被观察到：随着乳状液变得致密，我们发现了两个老化区域，它们之间存在交叉。这种年轻的乳状液在拥挤的环境中具有更快的动力学，并伴随着局部重排。尽管我们的研究表明，运动与较大的间歇性事件有关，但较旧的乳剂的动力学变慢了。从强度自相关函数可以看出，弛豫速率始终线性依赖于波矢；然而，与线形相关的指数从年轻样品的1.5变化到小于1的乳化液老化。据我们所知，类似弹道的动力学(指数降至1以下)和大的间歇性波动的组合以前从未报道过。
We use x-ray photon correlation spectroscopy to investigate the dynamics of a high-volume-fraction emulsion creaming under gravity. The dodecane-in-water emulsion has interfaces stabilized solely by colloidal particles (silica). The samples were observed soon after mixing: as the emulsion becomes compact we discern two regimes of aging with a crossover between them. The young emulsion has faster dynamics associated with creaming in a crowded environment accompanied by local rearrangements. The dynamics slow down for the older emulsion, although our studies show that motion is associated with large intermittent events. The relaxation rate, as seen from the intensity autocorrelation function, depends linearly on the wave vector at all times; however, the exponent associated with the line shape changes from 1.5 for young samples to less than 1 as the emulsion ages. The combination of ballisticlike dynamics, an exponent that drops below 1, and large intermittent fluctuations has not been reported before to our knowledge.