School of Physics and Astronomy and Nottingham Nanotechnology and Nanoscience Centre, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom.
Langmuir. 2011 Aug 2;27(15):9367-71. doi: 10.1021/la201984y. Epub 2011 Jul 8.
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 by passing 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° to 160 ± 5°. 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.
使用一种简单的光学检测技术监测了小（微升）液滴在固体基底上的共振振动。使用一小股空气向液滴施加脉冲，并通过穿过液滴的激光束和使用简单的光电二极管装置测量散射光强度的变化来监测其随时间的振荡。然后对所得的随时间变化的强度变化进行傅里叶变换，以获得关于液滴振动频率的信息。在接触角范围为 12 ± 4°至 160 ± 5°的表面上，获得了质量在 0.005-0.03 克范围内的液滴的共振频率。发现液滴的共振频率与一个简单的理论非常吻合，该理论考虑了液滴子午轮廓长度上的驻波状态。
