Paint drop spreading on wood and its enhancement by an in-plane electric field
Paint drop spreading on wood and its enhancement by an in-plane electric field
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DOI：
10.1063/5.0130871
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发表时间：
2022-12
影响因子：
4.6
通讯作者：
R. Granda;Vitaliy Yurkiv;F. Mashayek;A. Yarin
中科院分区：
文献类型：
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作者：
R. Granda;Vitaliy Yurkiv;F. Mashayek;A. Yarin
苯胺染料的水滴柔和地定位或冲击到轻木基板上的实验观察被用来阐明面内电场（在施加10 kV的高电压下）对水滴行为的影响。同时记录顶视图和侧视图。短期记录（在几毫秒的尺度上）证明了所施加的面内电场的轻微影响。在一些试验中，与没有施加电压的试验相比，沿着液滴边缘观察到更多数量的指状结构沿着。这些指状物是在下降边缘的前进运动期间形成的。使用长期记录（在10秒的尺度上）来评估润湿性驱动的润湿区域的面积等效半径的增加。这些基板在电极间或交叉场方向上具有凹槽。沟槽方向影响润湿性驱动的铺展和自吸。从长远来看，润湿性驱动的扩散比电场的效果显著得多，因为吸胀显著地减少了多孔表面上方的液滴部分，这又减少了可以拉伸液滴的电麦克斯韦应力。在这些实验中，开发了一个简化的分析模型来测量负责液体吸胀的水分传输系数。此外，相场法模拟了液滴在轻木上的吸附过程，以说明接触角从疏水性变为亲水性是如何触发液滴向轻木中的吸胀的。
Experimental observations of drops of water with aniline dye softly located or impacting onto balsa wood substrates were used to elucidate the effect of an in-plane electric field (at a high voltage of 10 kV applied) on drop behavior. The top and side views were recorded simultaneously. The short-term recordings (on the scale of a few ms) demonstrated a slight effect of the applied in-plane electric field. In some trials, a greater number of finger-like structures were observed along the drop rim compared to the trials without voltage applied. These fingers developed during the advancing motion of the drop rim. The long-term recording (on the scale of ∼10 s) was used to evaluate the wettability-driven increase in the area-equivalent radius of the wetted area. These substrates had grooves in the inter-electrode or the cross-field directions. The groove directions affected the wettability-driven spreading and imbibition. The wettability-driven spreading in the long term was a much more significant effect than the effect of the electric field, because the imbibition significantly diminished the drop part above the porous surface, which diminished, in turn, the electric Maxwell stresses, which could stretch the drop. A simplified analytical model was developed to measure the moisture transport coefficient responsible for liquid imbibition in these experiments. Furthermore, the phase-field modeling of drops on balsa was used to illustrate how a change in the contact angle from hydrophobic to hydrophilic triggers drop imbibition into balsa wood.