Contact Angle Dependence of the Resonant Frequency of Sessile Water Droplets
Contact Angle Dependence of the Resonant Frequency of Sessile Water Droplets
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DOI：
10.1021/la201984y
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发表时间：
2011-08-02
期刊：
影响因子：
3.9
通讯作者：
Kelly, James
中科院分区：
文献类型：
--
作者：
Sharp, James S.;Farmer, David J.;Kelly, James
采用一种简单的光学检测技术，对固体基板上支撑的小（微升）无底水滴的共振振动进行了监测。一小股空气被用来对液滴施加脉冲，通过一束激光穿过液滴来监测它们随时间的振荡，并使用一个简单的光电二极管来测量散射光强度的变化。由此产生的随时间的强度变化进行傅里叶变换，以获得有关液滴振动频率的信息。在水接触角为12 +/- 4°~ 160 +/- 5°的表面上，得到了质量为0.005 ~ 0.03 g的液滴的共振频率。发现液滴谐振频率与接触角的依赖关系与考虑沿子午剖面长度的驻波状态的简单理论很好地一致。
The resonant vibrations of small (microliter) sessile water droplets supported on solid substrates were monitored using a simple optical detection technique. A small puff of air was used to apply an impulse to the droplets and their time dependent oscillations were monitored bypassing a laser beam through the droplet and measuring the variations of the intensity of the scattered light using a simple photodiode arrangement. The resulting time dependent intensity changes were then Fourier transformed to obtain information about the vibrational frequencies of the droplets. The resonant frequencies of droplets with masses in the range 0.005-0.03 g were obtained on surfaces with water contact angles ranging from 12 +/- 4 degrees to 160 +/- 5 degrees. The contact angle dependence of the resonant frequency of the droplets was found to be in good agreement with a simple theory which considers standing wave states along the meridian profile length of the droplets.