Weak Forces for the Growth of Smectic-F Liquid Crystal
作者:
D.M. Potukuchi,
G.Padmaja Rani,
M. Srinivasulu,
V.G.K.M. Pisipati,
期刊:
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals
(Taylor Available online 1998)
卷期:
Volume 319,
issue 1
页码: 19-29
ISSN:1058-725X
年代: 1998
DOI:10.1080/10587259808045644
出版商: Taylor & Francis Group
关键词: 120.m compounds of n0.m series;smectic-F;miscibility studies;phase diagram;Van der Walls' forces
数据来源: Taylor
摘要:
N(p-n-dodecyloxybenzylidene)p-n-alkylanilines, viz., 120.mcompounds ofnO.mseries, form= 4, 5, 6, 8, 10, 12, 14 and 16 are synthesised and characterised by Polarised Thermal Microscopy (TM) and Differential Scanning Calorimetry (DSC). These compounds are found to exhibit 2D Bond-Orientationally (BO) ordered smectic-F liquid crystal phase with shift distortion along with orthogonal smectic-A, -B(cryst) phases. The intermediate members of the compounds of 120.mseries (m< 10) are found to exhibit orthogonal smectic phases along with the tilted phases, while the higher homologues (m> 10) show the tilted bond-orientational smectic phases only. The miscibility studies for the confirmation of smectic-F phase through binary (120.12 + 100.14) phase diagram, suggests the possibility for the occurrence of smectic-F phase down towards ambient temperatures. The smectic-G phase melting temperature,TFGis found to depress at lower and higher concentrations (x), while smectic-F phase clearing temperatureTIFremains constant with the concentration. The thermal span of smectic-F phase is found to depend on the chemical potential (represented by the mole fractionx) in the (T, x) phase diagram. The cubic fit in the vicinity of lower/higher concentrations, qualitatively infers the weak nature of Van der Walls' molecular forces for the growth of pseudo-hexagonal packed quasi-2-D BO orderedSFliquid crystal with a poor registry of positional correlations.
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