Anomalous diffusion and power-law relaxation of the time averaged mean squared displacement in worm-like micellar solutions
Anomalous diffusion and power-law relaxation of the time averaged mean squared displacement in worm-like micellar solutions
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DOI：
10.1088/1367-2630/15/4/045011
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发表时间：
2013-04-17
影响因子：
3.3
通讯作者：
Metzler, Ralf
中科院分区：
文献类型：
--
作者：
Jeon, Jae-Hyung;Leijnse, Natascha;Metzler, Ralf
我们报告的结果，单示踪粒子跟踪的光镊和视频显微镜在胶束溶液。根据不同的随机模型，通过仔细分析，我们发现尺寸为0.52-2.5 μ m的聚苯乙烯示踪珠在短时间正常扩散后，会发生< r（2）（t）>类似或等于t（α）的反常扩散，α近似为0.3。这种自由的反常扩散是遍历性的，并且与具有幂律记忆核的广义朗之万方程的描述一致。利用光镊跟踪，我们揭示了在谐波镊子势的限制下，在几十年的时间内到热平台值的幂律弛豫，如先前所预测的（Phys.Rev.E85021147（2012））。在毫秒范围内的亚扩散运动之后，运动变得更快，并且取决于示踪珠的大小，或者回到正常的布朗扩散，或者甚至更快的超扩散。
We report the results of single tracer particle tracking by optical tweezers and video microscopy in micellar solutions. From careful analysis in terms of different stochastic models, we show that the polystyrene tracer beads of size 0.52-2.5 mu m after short-time normal diffusion turn over to perform anomalous diffusion of the form < r(2)(t)> similar or equal to t(alpha) with alpha approximate to 0.3. This free anomalous diffusion is ergodic and consistent with a description in terms of the generalized Langevin equation with a power-law memory kernel. With optical tweezers tracking, we unveil a power-law relaxation over several decades in time to the thermal plateau value under the confinement of the harmonic tweezer potential, as predicted previously (Phys. Rev. E 85 021147 (2012)). After the subdiffusive motion in the millisecond range, the motion becomes faster and turns either back to normal Brownian diffusion or to even faster superdiffusion, depending on the size of the tracer beads.