Thermal gradient-induced patterning

The topics presented here are a subset of self-organization and pattern formation processes, which are also seen in various other settings such as evaporation, condensation, elastic instabilities in various materials including elastomers, block copolymers, blends, and liquid crystals. An interested reader is advised to consult some excellent review papers on each of the themes, some of which are cited in the reference section. 

The authors would like to acknowledge the funding from a DST- UKIERI project. 

12 Madou, M.J. (2002) Fundamentals of Microfabrication The Science of Miniaturization, 2nd edn, CRC Press, Boca Raton, FL. 

26 Langbein, D. (2002) Capillary Surfaces, Springer-Verlag, Berlin. 

29 Landau, L.D. and Lifshilz, E.M. (1960) Electrodynamics of Continuous Media, Pergamon, Oxford, pp. 368-376. 

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Electrohydrodynamic patterning/Thermal-gradient induced surface patterning. A stable liquid polymer film becomes unstable when the surface tension is overcome... 

From the results of RTD studies it can be concluded that small changes in bowl temperatures above or below the feed temperature have a significant effect on flow patterns in the bowl. This result supports the hypothesis that thermally induced density gradients lead to mixing currents. In addition to temperature, flow patterns are affected by feed flow rate and bowl speed. Separation efficiency and classification studies show that the various flow patterns produced under different operating conditions affect separation performance in both types of separations studied. This fact leads to the conclusion that flow patterns must be better understood and controlled in order to optimize classification of superfine solids. 

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