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Emergence of a linear slope region of the isotherm in the first-order liquid-expanded-liquid-condensed phase transition in Langmuir monolayers
Title: | Emergence of a linear slope region of the isotherm in the first-order liquid-expanded-liquid-condensed phase transition in Langmuir monolayers |
Authors: | Hatta, Eiji Browse this author →KAKEN DB | Nihei, Ko Browse this author |
Issue Date: | 1-Aug-2019 |
Publisher: | American Physical Society (APS) |
Journal Title: | Physical Review E |
Volume: | 100 |
Issue: | 2 |
Start Page: | 022801 |
Publisher DOI: | 10.1103/PhysRevE.100.022801 |
Abstract: | A nonhorizontal slope in the isotherm has been observed in the two-phase coexisting region of the first-order liquid-expanded (LE)-liquid-condensed (LC) phase transition in Langmuir monolayers for many decades. We show that the simple analysis of a phenomenological Landau free energy involving the coupling-energy contributions of molecular lateral density (rho) with spontaneous collective chain tilt (theta) and two-dimensional strain (epsilon(s)) inside the LC domain enables one to understand the origin of a nonhorizontal straight-line slope in the LE-LC phase coexistence region of the isotherm. The presence of rho - epsilon(s) coupling must be essential for the appearance of the straight-line shape of a nonhorizontal plateau in the isotherm. Moreover, it is found from the comparison of the two-dimensional contour plots of the free energy that an LE phase may persist significantly even at the later stage of the straight-line regime beyond a transition midpoint surface pressure in the presence of this coupling. The persistence of the LE phase may lead to the delay of transition progress as manifested more clearly by the appearance of a compressibility plateau in the coexistence region that indicates the existence of persistent equilibrium density fluctuations in the monolayer. |
Rights: | ©2019 American Physical Society |
Type: | article |
URI: | http://hdl.handle.net/2115/75367 |
Appears in Collections: | 情報科学院・情報科学研究院 (Graduate School of Information Science and Technology / Faculty of Information Science and Technology) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 八田 英嗣
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