Electrohydrodynamic convection instabilities observed in suspensions of cellulose nanocrystals.
Electrohydrodynamic convection instabilities observed in suspensions of cellulose nanocrystals.
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DOI：
10.1007/s10570-023-05391-6
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发表时间：
2023
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影响因子：
--
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中科院分区：
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--
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纤维素纳米晶体是细长的，带负电荷的纳米颗粒，在超过临界浓度的水悬浮液中自发形成胆甾型液晶。当它们用表面活性剂悬浮在极性溶剂（如甲苯）中时，施加交流电场会导致胆甾酯结构的重定向和扭曲，直到胆甾酯结构完全解绕成向列状结构，通常在1kHz时高于0.4-0.6 kV/cm。在这项工作中，我们证明了在更高的电场（4.6 kV/cm, 1khz）下，样品呈现出随电场振幅变化的周期性图案。我们将这种模式归因于电流体动力对流的不稳定性。这些不稳定性通常呈现复杂的状态，随场、电压、频率和几何形状而变化。然而，这些不稳定性在文献中记录最多的典型几何与本工作中使用的几何不同。这项工作的结论可能是未来的实验研究，以澄清造成这些观察结果的不稳定性的确切机制。在线版本包含补充材料，可在10.1007/s10570-023-05391-6获得。
Cellulose nanocrystals are slender, negatively charged nanoparticles that spontaneously form a cholesteric liquid crystal in aqueous suspension above a critical concentration. When they are suspended in apolar solvents such as toluene using surfactants, the application of an AC electric field leads to the reorientation and then distortion of the cholesteric order until the cholesteric structure completely unwinds into a nematic-like order, typically above 0.4–0.6 kV/cm at 1kHz. In this work, we show that at much higher electric fields ( 4.6 kV/cm at 1 kHz) the sample develops a periodic pattern that varies with the field amplitude. We ascribed this pattern to electrohydrodynamic convection instabilities. These instabilities usually present complex regimes varying with the field, the voltage, the frequency and the geometry. However, the typical geometry where these instabilities were most documented across the literature differs from the geometry used in this work. This work concludes with possible future experimental investigations to clarify the exact regime of instability responsible for these observations. The online version contains supplementary material available at 10.1007/s10570-023-05391-6.
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影响因子：
2.1
作者：
DEGENNES, PG
通讯作者：
DEGENNES, PG
影响因子：
3.9
作者：
Dogic, Z;Fraden, S
通讯作者：
Fraden, S
影响因子：
3.3
作者：
Elazzouzi-Hafraoui, Samira;Putaux, Jean-Luc;Heux, Laurent
通讯作者：
Heux, Laurent
影响因子：
4.4
作者：
WILLIAMS, R
通讯作者：
WILLIAMS, R
影响因子：
3.9
作者：
Heux, L;Chauve, G;Bonini, C
通讯作者：
Bonini, C