RT Journal Article
T1 Enhanced stability of the tetratic phase due to clustering
A1 Martínez-Ratón, Yuri
A1 Velasco, Enrique
AB We show that the relative stability of the nematic tetratic phase with respect to the usual uniaxial nematic phase can be greatly enhanced by clustering effects. Two-dimensional rectangles of aspect ratio κ interacting via hard interactions are considered, and the stability of the two nematic phases (uniaxial and tetratic) is examined using an extended scaled-particle theory applied to a polydispersed fluid mixture of n species. Here the ith species is associated with clusters of i rectangles, with clusters defined as stacks of rectangles containing approximately parallel rectangles, with frozen internal degrees of freedom. The theory assumes an exponential cluster size distribution (an assumption fully supported by Monte Carlo simulations and by a simple chemical-reaction model), with fixed value of the second moment. The corresponding area distribution presents a shoulder, and sometimes even a well-defined peak, at cluster sizes approximately corresponding to square shape (i.e., i ≃ κ), meaning that square clusters have a dominant contribution to the free energy of the hard-rectangle fluid. The theory predicts an enhanced region of stability of the tetratic phase with respect to the standard scaled-particle theory, much closer to simulation and to experimental results, demonstrating the importance of clustering in this fluid.
PB The American Physical Society
SN 1539-3755
YR 2009
FD 2009-01
LK https://hdl.handle.net/10016/6981
UL https://hdl.handle.net/10016/6981
LA eng
NO 9 pages, 10 figures.-- PACS nrs.: 61.30.Cz, 61.30.Hn, 61.20.Gy.-- ArXiv pre-print available at: http://arxiv.org/abs/0809.4200
NO Y.M.-R. gratefully acknowledges financial support from Ministerio de Educación y Ciencia (Spain) under a Ramón y Cajal research contract and a MOSAICO grant. This work has been partly financed by Grant Nos. FIS2005-05243-C02-01 and FIS2007-65869-C03-01, also from Ministerio de Educación y Ciencia, and Grant No. S-0505/ESP-0299 fromComunidad Autónoma de Madrid (Spain).
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RD 20 may. 2024