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Title: | Studies on binary mixtures of systems which exhibit a maximum as well as a minimum in the A-N transition boundary |
Authors: | Srikanta, B.S. Madhusudana, N.V. |
Issue Date: | Oct-1983 |
Publisher: | Gordon and Breach Science Publishers. |
Citation: | Molecular Crystals and Liquid Crystals, 1983, Vol.99, p203-221 |
Abstract: | We have studied the binary phase diagrams of (I) p'-nitrophenyl-p-n-octyloxybenzoate with (2-hydroxy)-p-ethoxybenzylidene-p'-butylaniline, and (II) p'-n-octyloxy-p-cyanobiphenyl with p-butoxyphenyl-(p'-pentyloxy)benzoate. Both of them show a strong maximum in the A-N boundary, indicative of an induced A phase, and further, a well defined minimum for a composition rich in the highly polar component. The interactions responsible for the induced phase are much stronger for the system II than for the system I. We have investigated the temperature variations of the layer spacings for various compositions of both the systems. In system I, there is a considerable thermal expansion of the spacing, the expansion coefficient attaining a maximum value for the composition corresponding to the minimum in the A-N boundary. We have given a physical interpretation of this observation. The dielectric anisotropies of various compositions of system I have also been investigated and their temperature dependences interpreted in terms of the physical model mentioned above. The conductivity anisotropy changes sign for all compositions exhibiting the A phase. The temperature of crossover in relation to TAN is the highest for the mixture which exhibits the minimum value of TAN, since the A-N transition is almost of a second order character for this composition. |
Description: | Restricted Access. Paper presented at the 9th international conference on liquid crystals held at Bangalore in 1982. |
URI: | http://hdl.handle.net/2289/2499 |
ISSN: | 1058-725X |
Alternative Location: | http://arxiv.org/abs/cond-mat/ http://dx.doi.org |
Copyright: | 1983 OPA (Overseas Publishers Association) N.V. |
Appears in Collections: | Research Papers (SCM) |
Files in This Item:
File | Description | Size | Format | |
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1983 MCLC V99 p203.pdf Restricted Access | Restricted Access | 477.62 kB | Adobe PDF | View/Open Request a copy |
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