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Title: Surface properties of aqueous polymer solutions
Author: Scott, John Clifford
Awarding Body: University of London
Current Institution: Imperial College London
Date of Award: 1971
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The reduction of turbulent flow energy dissipation is of considerable importance in many high speed liquid flow situations. Oscillating flow techniques represent a fairly reproducible means of examining the flow properties of the materials which promote the phenomenon of "drag reduction", and the present work concerns the application of one type of acoustic excitation to the investigation of polymer materials which are very effective in the reduction of turbulent drag in water. Systems of transverse surface waves, or ripples, were examined, and it was found that the properties of ripples on the surface of drag-reducing polymer solutions were much less dependent on the flow properties of the bulk liquid than on the presence of surface activity in the solutions. In one of the polymer series examined, that of poly(ethylene oxide), the surface activity completely dominated the ripple propagation. Reviews are given of the surface properties of liquids in general, polymer solutions in particular, and of the factors determining the propagation of liquid surface waves. A completely new technique of ripple measurement developed for this investigation, using moire fringes, is described, and results are presented of measurements on poly(ethylene oxide)/water systems using this technique. Although certain experimental imperfections concerned with surface contamination are indicated by the results, the distinctive ripple damping behaviour of poly(ethylene oxide) has been shown to support the conclusions of modern hydrodynamic ripple theory. Evidence is also presented which suggests that this particular polymer exhibits adsorption characteristics not previously reported: A certain "irreversibility" in the adsorption appears to exist at the air/water surface which results in the production of strong surface activity effects at very low polymer concentrations.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available