1H Nuclear Magnetic Resonance Study of an Incommensurate-Commensurate Phase Transition in a Dimesogenic Liquid Crystal

Kyung Oh Kim; Dong Min Choi; Cheol Eui Lee; Jung Il Jin

doi:10.3938/jkps.72.838

¹H Nuclear Magnetic Resonance Study of an Incommensurate-Commensurate Phase Transition in a Dimesogenic Liquid Crystal

Kyung Oh Kim, Dong Min Choi, Cheol Eui Lee, Jung Il Jin

Department of Physics

Research output: Contribution to journal › Article › peer-review

Abstract

¹H nuclear magnetic resonance (NMR) was employed in order to probe an incommensuratecommensurate phase transition in a dimesogenic liquid crystal, N-[4-(6-cholesteryloxycarbonyl) pentyloxy]-4-n-butylazobenzene (KI5A). The recrystallization and the isotropic phase transitions exhibited a discontinuous first-order nature in the ¹H NMR spin-lattice (T₁) and in the spin-spin relaxation time (T_2E) measurements, and an incommensurate smectic A (S_Ainc) to commensurate helical smectic C (S*_C) liquid crystalline phase transition was marked by a discontinuity in the NMR line splitting representing the orientational order. Furthermore, T₁ and T_2E showed distinct temperature dependencies in the S_Ainc phase and in the S*_C phase.

Original language	English
Pages (from-to)	838-840
Number of pages	3
Journal	Journal of the Korean Physical Society
Volume	72
Issue number	7
DOIs	https://doi.org/10.3938/jkps.72.838
Publication status	Published - 2018 Apr 1

Keywords

Commensurate-incommensurate phase transition
Dimesogenic liquid crystal
H nuclear magnetic resonance

ASJC Scopus subject areas

Physics and Astronomy(all)

Access to Document

10.3938/jkps.72.838

Cite this

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title = "1H Nuclear Magnetic Resonance Study of an Incommensurate-Commensurate Phase Transition in a Dimesogenic Liquid Crystal",

abstract = "1H nuclear magnetic resonance (NMR) was employed in order to probe an incommensuratecommensurate phase transition in a dimesogenic liquid crystal, N-[4-(6-cholesteryloxycarbonyl) pentyloxy]-4-n-butylazobenzene (KI5A). The recrystallization and the isotropic phase transitions exhibited a discontinuous first-order nature in the 1H NMR spin-lattice (T1) and in the spin-spin relaxation time (T2E) measurements, and an incommensurate smectic A (SAinc) to commensurate helical smectic C (S*C) liquid crystalline phase transition was marked by a discontinuity in the NMR line splitting representing the orientational order. Furthermore, T1 and T2E showed distinct temperature dependencies in the SAinc phase and in the S*C phase.",

keywords = "Commensurate-incommensurate phase transition, Dimesogenic liquid crystal, H nuclear magnetic resonance",

author = "Kim, {Kyung Oh} and Choi, {Dong Min} and Lee, {Cheol Eui} and Jin, {Jung Il}",

note = "Funding Information: This work was supported by the National Research Foundation of Korea (Project No. 2016R1D1A1A09917003). The Korea Basic Science",

year = "2018",

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doi = "10.3938/jkps.72.838",

language = "English",

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T1 - 1H Nuclear Magnetic Resonance Study of an Incommensurate-Commensurate Phase Transition in a Dimesogenic Liquid Crystal

AU - Kim, Kyung Oh

AU - Choi, Dong Min

AU - Lee, Cheol Eui

AU - Jin, Jung Il

N1 - Funding Information: This work was supported by the National Research Foundation of Korea (Project No. 2016R1D1A1A09917003). The Korea Basic Science

PY - 2018/4/1

Y1 - 2018/4/1

N2 - 1H nuclear magnetic resonance (NMR) was employed in order to probe an incommensuratecommensurate phase transition in a dimesogenic liquid crystal, N-[4-(6-cholesteryloxycarbonyl) pentyloxy]-4-n-butylazobenzene (KI5A). The recrystallization and the isotropic phase transitions exhibited a discontinuous first-order nature in the 1H NMR spin-lattice (T1) and in the spin-spin relaxation time (T2E) measurements, and an incommensurate smectic A (SAinc) to commensurate helical smectic C (S*C) liquid crystalline phase transition was marked by a discontinuity in the NMR line splitting representing the orientational order. Furthermore, T1 and T2E showed distinct temperature dependencies in the SAinc phase and in the S*C phase.

AB - 1H nuclear magnetic resonance (NMR) was employed in order to probe an incommensuratecommensurate phase transition in a dimesogenic liquid crystal, N-[4-(6-cholesteryloxycarbonyl) pentyloxy]-4-n-butylazobenzene (KI5A). The recrystallization and the isotropic phase transitions exhibited a discontinuous first-order nature in the 1H NMR spin-lattice (T1) and in the spin-spin relaxation time (T2E) measurements, and an incommensurate smectic A (SAinc) to commensurate helical smectic C (S*C) liquid crystalline phase transition was marked by a discontinuity in the NMR line splitting representing the orientational order. Furthermore, T1 and T2E showed distinct temperature dependencies in the SAinc phase and in the S*C phase.

KW - Commensurate-incommensurate phase transition

KW - Dimesogenic liquid crystal

KW - H nuclear magnetic resonance

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