Crack Formation on a Drying Droplet in the Presence of Static Electric Field

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Authors

  • Condensed Matter Physics Research Centre, Jadavpur University, Kolkata-700 032 ,IN
  • Physics Department, St. Xavier's College, Kolkata-700 017 ,IN
  • Condensed Matter Physics Research Centre, Jadavpur University, Kolkata-700 032 ,IN

DOI:

https://doi.org/10.18311/jsst/2014/1853

Keywords:

Gel Droplet, Electric Field, Crack Formation, Scaling Relation.

Abstract

The formation of crack patterns in a drying droplet of Laponite is studied under a DC (direct current) field. Though in the absence of a field, the droplet produces no crack on drying, it gives remarkable and reproducible results in the presence of a radial field. Cracks always appear from positive electrode and propagate towards the negative electrode and water seeps out from the negative electrode. When the centre electrode is negative, small cracks appear from outer periphery and the central portion remains almost free of crack. The behavior of cracks depends on the strength, direction and duration of application of field. The patterns show a typical memory effect different from 'Nakahara effect'. We name this as 'persistence memory'. From SEM (Scanning Electron Microscopy) images, it is seen that there are some striation marks left on the cracked surface, similar to cracks in larger systems.