Temperton Robert H, Hill Richard J A, Sharp James S
School of Physics and Astronomy and Nottingham Nanotechnology and Nanoscience Centre, University of Nottingham, Nottingham, UK.
Soft Matter. 2014 Aug 7;10(29):5375-9. doi: 10.1039/c4sm00982g. Epub 2014 Jun 18.
The mechanical vibrations of magnetically levitated droplets were investigated using a simple optical deflection technique. Droplets of water and a water-based solution of poly(acrylamide-co-acrylic acid) were levitated in the bore of a superconducting magnet and perturbed with a short puff of air. Centre of mass and surface vibrations were monitored using laser light refracted through the droplet, focussed on to the end of an optical fiber and detected using a photodiode. Time dependent variations in the voltage generated by the photodiode were Fourier transformed to obtain the frequency and spectral width of the drops' mechanical resonances. A simple theory of drop vibration was developed to extract the rheological properties of the droplets from these quantities. The resulting values of G' and G'' that were extracted were found to be in good agreement with values obtained using conventional rheology techniques.
利用一种简单的光学偏转技术研究了磁悬浮液滴的机械振动。水和聚丙烯酰胺 - 丙烯酸共聚物的水基溶液液滴悬浮在超导磁体的孔中，并用一阵短暂的气流进行扰动。通过液滴折射的激光监测质心和表面振动，激光聚焦在光纤末端并使用光电二极管进行检测。对光电二极管产生的随时间变化的电压进行傅里叶变换，以获得液滴机械共振的频率和频谱宽度。建立了一个简单的液滴振动理论，从这些量中提取液滴的流变特性。所提取的G'和G''的结果值与使用传统流变学技术获得的值非常吻合。
