Investigation into liquid crystalline smectic-C* subphase stability using chiral and achiral dopants

Journal Article · Thu Nov 15 04:00:00 EST 2007 · Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics

DOI:https://doi.org/10.1103/PHYSREVE.76.051704· OSTI ID:21076264

Kirchhoff, J; Hirst, L S ^[1]

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1. MARTECH, Department of Physics, Florida State University, Florida 32306 (United States)

In this paper we investigate the influence of chiral and achiral dopants on a chiral smectic liquid crystal material, which exhibits a rich phase sequence, including the antiferroelectric phase and the three-layer intermediate smectic (SmC*{sub FI1}) phase. Using polarized optical microscopy, differential scanning calorimetry, and x-ray diffraction we find that small amounts of achiral dopant have the ability to significantly broaden the SmC*{sub FI1} phase, whereas an oppositely-handed dopant (otherwise identical to the host material) destabilizes the phase. This work clearly indicates that bulk chirality strongly influences SmC*{sub FI1} phase formation and that steric effects also play an important role. Interestingly, addition of the shorter achiral molecule (8CB) was observed to increase the smectic layer spacing, most likely by suppressing interdigitation of alkyl chains between adjacent smectic layers. Control of the SmC*{sub FI1} phase width using mixtures in this way is clearly important for effective phase characterization, and could potentially lead to commercially viable materials with a stable SmC*{sub FI1} phase over a large temperature range.

• OSTI ID: 21076264
• Journal Information: Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, Journal Name: Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics Journal Issue: 5 Vol. 76; ISSN PLEEE8; ISSN 1063-651X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CALORIMETRY
DOPED MATERIALS
LAYERS
LIQUID CRYSTALS
MIXTURES
OPTICAL MICROSCOPY
X-RAY DIFFRACTION