The STUDIA UNIVERSITATIS BABEŞ-BOLYAI issue article summary

The summary of the selected article appears at the bottom of the page. In order to get back to the contents of the issue this article belongs to you have to access the link from the title. In order to see all the articles of the archive which have as author/co-author one of the authors mentioned below, you have to access the link from the author's name.

 
       
         
    STUDIA CHEMIA - Issue no. 3 / 2007  
         
  Article:   ON THE DYNAMICS OF FREE DROPS.

Authors:  MARIA TOMOAIA-COTISEL, EUGENIA GAVRILA, IOSIF ALBU, IOAN-RĂDUCAN STAN.
 
       
         
  Abstract:  This is a review on the original work by Chifu et al. that explored the various movements of the free drops. This review also presents some theoretical models and experiments further developed by the academic research group, established by him in the physical chemistry department, to deeply investigate the free drop dynamics and related interfacial phenomena. The interfacial tension gradient caused by the surfactant adsorption at the surface of a free liquid drop gives rise to a surface flow (i.e. Marangoni interfacial flow) which causes the motion of the neighboring liquids by viscous traction, and generates a hydrodynamic pressure force, named Marangoni force, which acts on the drop surface. The effect of the surfactant adsorption and of Marangoni force on the dynamics of free liquid drops immersed in an unbounded liquid (the densities of the two bulk liquids are equal) is studied. Marangoni force was examined on several cases using non-deformable and deformable free drops. For a low value of the viscosity ratio of the two liquids (i.e., the drop liquid viscosity /unbounded liquid viscosity) at a high interfacial tension gradient, a dynamic instability of the drop was experimentally observed. This instability once triggered develops into the fragmentation of the drop into two droplets. For high values of the viscosity ratio of the two bulk liquids at a high interfacial tension gradient, only drop deformations appear. In the situation of a very high viscosity ratio and at a small interfacial tension gradient the drops are undeformable. The observed experimental data are in a substantial agreement with the results of our hydrodynamic theoretical model.  
         
     
         
         
      Back to previous page