When a colloidal gel dries through evaporation, cracks are usually formed,which often reveal underlying processes at work during desiccation. Desiccatingcolloid droplets of few hundred $\mu l$ size show interesting effects ofpattern formation and cracking which makes this an active subject of currentresearch. Since aqueous gels of clay are known to be strongly affected by anelectric field, one may expect crack patterns to exhibit a field effect. In thepresent study we allow droplets of laponite gel to dry under a radial electricfield. This gives rise to highly reproducible patterns of cracks, which dependon the strength, direction and time of exposure to the electric field. For acontinuously applied DC voltage, cracks always appear on dissipation of acertain constant amount of energy. If the field is switched off before cracksappear, the observed results are shown to obey a number of empirical scalingrelations, which enable us to predict the time of appearance and the number ofcracks under specified conditions.
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