Active turbulence and spontaneous phase separation in inhomogeneous extensile active gels.
Active turbulence and spontaneous phase separation in inhomogeneous extensile active gels.
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非均匀可拉伸活性凝胶中的活性湍流和自发相分离。
DOI：
10.1039/d2sm01188c
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发表时间：
2023
期刊：
影响因子：
3.4
通讯作者：
Assante R
中科院分区：
文献类型：
--
作者：
Assante R
我们报告了非均匀溶致凝胶和可拉伸活性向列凝胶的流体动力学数值结果。通过模拟耦合的 Cahn-Hilliard、Navier-Stokes 和 Beris-Edwards 方程来描述活性向列相的成分、流动和取向顺序的演化，我们询问成分变化是否对于确定其新兴物理现象很重要。正如在均匀成分的活性凝胶中一样，我们发现增加活性或向列倾向（例如，总体活性物质浓度）会触发各向同性钝相和活性向列相之间的转变。我们表明，成分不均匀性在后一阶段很重要，我们发现了三种可能的动力学机制。首先，我们观察到带有缺陷和涡流的规则模式：这些存在于被动-主动转变附近。其次，对于较大的活性，或在向列相中较深的活性，我们发现活性湍流，如在成分均匀的活性凝胶中，但成分变化非常大。在第三种状态中，它与不均匀性独特相关，并且因向列倾向大和活性低而发生，我们观察到自发微相分离为主动域和被动域。鉴于我们使用的基础自由能中缺乏明确的分层项，微相分离状态是值得注意的，并且我们提供了基于公切线结构的理论分析来解释其存在。我们希望将来能够对这一制度进行实验探索。
We report numerical results for the hydrodynamics of inhomogeneous lyotropic and extensile active nematic gels. By simulating the coupled Cahn–Hilliard, Navier–Stokes, and Beris–Edwards equation for the evolution of the composition, flow and orientational order of an active nematic, we ask whether composition variations are important to determine its emergent physics. As in active gels of uniform composition, we find that increasing either activity or nematic tendency (e.g., overall active matter concentration) triggers a transition between an isotropic passive phase and an active nematic one. We show that composition inhomogeneities are important in the latter phase, where we find three types of possible dynamical regimes. First, we observe regular patterns with defects and vortices: these exist close to the passive–active transition. Second, for larger activity, or deeper in the nematic phase, we find active turbulence, as in active gels of uniform composition, but with exceedingly large composition variation. In the third regime, which is uniquely associated with inhomogeneity and occurs for large nematic tendency and low activity, we observe spontaneous microphase separation into active and passive domains. The microphase separated regime is notable in view of the absence of an explicit demixing term in the underlying free energy which we use, and we provide a theoretical analysis based on the common tangent construction which explains its existence. We hope this regime can be probed experimentally in the future.
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影响因子：
44.1
作者：
Marchetti, M. C.;Joanny, J. F.;Simha, R. Aditi
通讯作者：
Simha, R. Aditi
相关性在微型游泳者悬浮液集体行为中的作用。
影响因子：
8.6
作者：
Joakim Stenhammar;C. Nardini;R. Nash;D. Marenduzzo;A. Morozov
通讯作者：
A. Morozov
浓缩胶体活性凝胶复合材料中的动态聚集和再分散。
影响因子：
3.4
作者：
G. Foffano;J. Lintuvuori;K. Stratford;M. Cates;D. Marenduzzo
通讯作者：
D. Marenduzzo
DOI：
10.1103/physreve.68.040101
发表时间：
2003
期刊：
Physical review. E, Statistical, nonlinear, and soft matter physics
影响因子：
--
作者：
Michael Wilkinson;Bernhard Mehlig
通讯作者：
Bernhard Mehlig
DOI：
10.1073/pnas.1912690117
发表时间：
2020-02-04
影响因子：
11.1
作者：
Martinez, Vincent A.;Clement, Eric;Poon, Wilson C. K.
通讯作者：
Poon, Wilson C. K.