Research output: Contribution to journal › Article › peer-review
Mesomorphism in columnar phases studied by solid-state nuclear magnetic resonance. / Dvinskikh, Sergey V.; Thaning, Johan; Stevensson, Baltzar; Jansson, Kjell; Kumar, Sandeep; Zimmermann, Herbert; Maliniak, Arnold.
In: Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, Vol. 74, No. 2, 021703, 15.08.2006.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Mesomorphism in columnar phases studied by solid-state nuclear magnetic resonance
AU - Dvinskikh, Sergey V.
AU - Thaning, Johan
AU - Stevensson, Baltzar
AU - Jansson, Kjell
AU - Kumar, Sandeep
AU - Zimmermann, Herbert
AU - Maliniak, Arnold
PY - 2006/8/15
Y1 - 2006/8/15
N2 - In this paper, we present C13 and H1 NMR investigations of 2, 3, 6, 7, 10, 11-hexahexyl-thiotriphenylene (HHTT). The measurements were carried out under both static and magic-angle spinning conditions. The phase diagram of HHTT is K↔H↔ Dhd↔I, where H is a helical phase and Dhd is a columnar liquid crystal. The motivation was to characterize the molecular order and dynamics and to investigate differences at the molecular level between the two mesophases: H and Dhd. It is shown that Dhd is a conventional columnar liquid crystal, where the molecular core undergoes fast rotation about the symmetry axis. The orientational order in this mesophase is lower and the temperature dependence of the order parameter is steeper than in other triphenylene-based compounds. On the other hand, in the helical phase the core, similarly to the solid phase, is essentially rigid. The difference between the solid and helical phases is mainly manifested in an increased mobility of the aliphatic chains observed in the latter phase. In addition, the sample exhibits thermal history effects, which are observed in the different behavior upon cooling and heating.
AB - In this paper, we present C13 and H1 NMR investigations of 2, 3, 6, 7, 10, 11-hexahexyl-thiotriphenylene (HHTT). The measurements were carried out under both static and magic-angle spinning conditions. The phase diagram of HHTT is K↔H↔ Dhd↔I, where H is a helical phase and Dhd is a columnar liquid crystal. The motivation was to characterize the molecular order and dynamics and to investigate differences at the molecular level between the two mesophases: H and Dhd. It is shown that Dhd is a conventional columnar liquid crystal, where the molecular core undergoes fast rotation about the symmetry axis. The orientational order in this mesophase is lower and the temperature dependence of the order parameter is steeper than in other triphenylene-based compounds. On the other hand, in the helical phase the core, similarly to the solid phase, is essentially rigid. The difference between the solid and helical phases is mainly manifested in an increased mobility of the aliphatic chains observed in the latter phase. In addition, the sample exhibits thermal history effects, which are observed in the different behavior upon cooling and heating.
UR - http://www.scopus.com/inward/record.url?scp=33746875961&partnerID=8YFLogxK
U2 - 10.1103/PhysRevE.74.021703
DO - 10.1103/PhysRevE.74.021703
M3 - Article
AN - SCOPUS:33746875961
VL - 74
JO - Physical Review E - Statistical, Nonlinear, and Soft Matter Physics
JF - Physical Review E - Statistical, Nonlinear, and Soft Matter Physics
SN - 1539-3755
IS - 2
M1 - 021703
ER -
ID: 48948122