Jumping of a droplet on a superhydrophobic surface in AC electrowetting
Jumping of a droplet on a superhydrophobic surface in AC electrowetting
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DOI：
10.1007/s12650-011-0076-z
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发表时间：
2011-08-01
影响因子：
1.7
通讯作者：
Kang, Kwan Hyoung
中科院分区：
文献类型：
--
作者：
Lee, Seung Jun;Lee, Sanghyun;Kang, Kwan Hyoung
通过引入超疏水表面而不是传统的疏水表面，实现了由AC电润湿驱动的一致的液滴弹跳。超疏水表面对于降低界面能障或粘附非常有效，允许液滴从基底完全脱离。当施加固定电位（100 V（rms））时，形状变形和液滴弹跳受交流电润湿频率的显著影响。一致的液滴弹跳仅发生在非常窄的频率范围（例如，对于8 μ L液滴为30-31 Hz），表明共振支配液滴弹跳。有趣的是，当液滴在空气中时，共振是1/2次谐波，其中跳过每隔一次的致动。基于线性理论的谐振频率的理论评估意味着AC电润湿和形状振荡的垂直振动之间的基本谐振对于产生一致的液滴弹跳可能是重要的。
Consistent droplet bouncing driven by AC electrowetting was achieved by introducing a superhydrophobic surface instead of conventional hydrophobic surfaces. A superhydrophobic surface is very effective to reduce interfacial energy barrier or adhesion, allowing complete detachment of a droplet from the substrate. While a fixed electric potential (100 V(rms)) was applied, the shape deformation and the droplet bouncing were significantly influenced by the frequency of the AC electrowetting. Consistent droplet bouncing only occurred at very narrow frequency ranges (e.g., 30-31 Hz for 8 mu L droplets), indicating that resonance dominates the droplet bouncing. Interestingly, the resonance was 1/2 sub-harmonics, where every other actuation was skipped, when the droplet was in the air. Theoretical evaluation of the resonant frequency based on the linear theory implies that the fundamental resonance between the AC electrowetting and the vertical vibration of the shape oscillation could be important to produce consistent droplet bouncing.