Self organization of liquid under external field-application to electrospinning and analogous phenomenon of Rayleigh-Plateau Instability

The present topic deals with framing and translating theoretical physics into a nanotechnology and, along with some relevant and analogous applications. It is notable that the pioneering and significant experimental work in the area of disintegration of liquid drops under electric field (Lukáš, Sarkar and Pokorný, 2008) that, strictly speaking, brought the area of ‘electrohydrodynamics’ under the purview of physical analysis, was carried out  during the early part of the 20th century. The groundbreaking theoretical work, based on Zeleny’s experiments, was put forward by Taylor (Lukáš, Sarkar and Pokorný, 2008). However, the theory could explain deformation of a liquid drop on a capillary, under static equilibrium condition of capillary and electric forces acting on the drop. 

The current effort aims at extending the already existing theory of capillary electrospinners to that of a free liquid surface electrospinner, using the idea of liquid surface perturbation under electric field (Lukáš, Sarkar and Pokorný, 2008). The theoretical modelling is accompanied by an instrumentation of a linear serrated cleft electrospinner. The electrohydrodynamic waves of perturbed liquid surface are observed vividly with the help of the clefts. Serrations help in local concentration of electric field on the liquid layer, by restricting the liquid overflow or leakage along / through the sides of the cleft, under action of an applied electric field. In this study, the whole system is modelled with some dimensionless parameters that normalise the phenomenon and, thereby, generalize Zeleny’s idea (Lukáš, Sarkar and Pokorný, 2008) for infinite free liquid surface. 

Since, physical fields are found to govern such phenomena, similar experiments are done with different relative orientations of electric and gravitational fields. The relative orientations of the fields are found to have a remarkable impact on electrohydrodynamic threshold conditions, i.e., initiation self organisation nature of electrospinning. Circular clefts were also designed and the dimensionless parameters for linear clefts fit reasonably well in this case also (Bhutani, Ahlawat, Sarkar, Mikes, Chvojka, Vodsedalkova, Lukáš, 2008). 
Some related analytical results, like wetting phenomenon of fibres, i.e. Rayleigh’s instability, are also used to draw analogy to the process of electrospinning (Lukáš, Pan, Sarkar, Ming, Chaloupek, Kostakova, Ocheretna, Mikes, and Pociute, 2008). 

References: 
Lukáš D, Sarkar A, Pokorný P (2008), ‘Self organization of jets in electrospinning from free liquid surface - a generalized approach’, Journal of Applied Physics, 103, 084309- 1-7; 
Bhutani N, Ahlawat M, Sarkar A, Mikes P, Chvojka J, Vodsedalkova K, and Lukáš D (2008), ‘Electrohydrodynamics of free liquid surface in a circular cleft: An application to electrospinning‘, The Fibre Society 200b Fall Annual Technical 

Conference, Quebec, Canada, October; 
Lukáš D, Pan N, Sarkar A, Ming W, Chaloupek J, Kostakova E, Ocheretna L, Mikes P and Pociute M (2010), ‘Auto-model based computer simulation of Rayleigh Instability of mixtures of immiscible liquids’, Physica A: Statistical Mechanics and its Applications, 389, Issue 11, 2164-2176.