A Molecular Mean Field Theory of Reentrant Phases |
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Authors: | T. R. Bose C. D. Mukherjee M. K. Roy M. Saha |
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Affiliation: | 1. Department of Physics , Calcutta University 92 , Acharya Prafulla Chandra Road, Calcutta, 700 009, India;2. Scottish Church College , Calcutta;3. Department of Physics , Calcutta University 92 , Acharya Prafulla Chandra Road, Calcutta, 700 009, India |
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Abstract: | The observed phase transition sequence N-SA-Nre Sre with a lowering in temperature in pure compounds of molecules with a strongly polar end group is reproduced in a mean field model which is taken as an extension of the McMillan potential. This model shows how the dimers in presence of space filling monomers can account for the high temperature SA phase. As the temperature is lowered, more and more monomers form dimers leaving empty spaces and this initiates an intercalation of dimers belonging to the neighbouring layers. This intercalation is responsible for the lowering of the strength of layering interaction in a McMillan type potential and thus a reentrant nematic phase occurs. This model for the first time successfully accounts for the thickness of the low temperature smectic phase. |
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Keywords: | heat-capacity discotic triphenylene polymorphism |
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