Resonant vibrations of microlitre liquid drops

Temperton, Robert H. (2013) Resonant vibrations of microlitre liquid drops. MSc(Res) thesis, University of Nottingham.

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The vibrational modes of water droplets supported on a surface (sessile drops) were excited by applying an impulse in the form of a short puff of nitrogen gas. An optical deflection technique was used to examine the modes of these oscillations in which laser light was scattered off the surface of the drops onto a photodiode. The time dependent intensity variations detected by the photodiode were Fourier transformed to give the vibrational spectra of the drops. The position and widths of the resonant peaks in these spectra were used along with a simple theory of droplet vibration to determine the surface tension and viscosity of the liquid. This theory models the resonant modes of the droplets as standing capillary wave states on the surface of a liquid bath of finite depth.

Surfaces patterned with parallel, periodic grooves were made using a variety of techniques. When a droplet of water was placed on one of these surfaces, the droplet was shown to wet anisotropically to the surface elongating the shape of the drop. The vibrational response of these aspherical droplets were measured as described above and the resulting vibrational spectra were shown to contain two closely spaced resonant peaks. These two peaks are shown to correspond to standing wave states forming along the profile lengths of the drop in the directions of the major and minor axes.

The vibrational response of droplets suspended from the end of a pipette tip (pendant drops) were also analysed using the same methods.

Item Type: Thesis (University of Nottingham only) (MSc(Res))
Supervisors: Sharp, J.S.
Subjects: Q Science > QC Physics
Faculties/Schools: UK Campuses > Faculty of Science > School of Physics and Astronomy
Item ID: 13162
Depositing User: EP, Services
Date Deposited: 02 Oct 2013 08:25
Last Modified: 14 Sep 2016 07:55

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