Splay and bend elastic constants in the nematic phase of some disulfide bridged dimeric compounds

Kundu, Brindaban ; Kumar Pal, Santanu ; Kumar, Sandeep ; Pratibha, R. ; Madhusudana, N. V. (2010) Splay and bend elastic constants in the nematic phase of some disulfide bridged dimeric compounds Physical Review E - Statistical, Nonlinear and Soft Matter Physics, 82 (6). 061703_1-061703_9. ISSN 1539-3755

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Official URL: http://pre.aps.org/abstract/PRE/v82/i6/e061703

Related URL: http://dx.doi.org/10.1103/PhysRevE.82.061703

Abstract

We report measurements of the temperature dependences of the splay (K11) and bend (K33) elastic constants of several homologues and a binary mixutre of disulfide bridged symmetric dimers made of alkoxy cyanobiphenyl monomeric units. All of them have an even number m of carbon and sulfur atoms in the linking chain and expected to have linear conformations. Both K11 and K33 alternate depending on the parity of x which is the number of carbon atoms in the alkyl chain of a monomer. We will refer to this as 'odd-even' effect. This effect, occurs near the nematic-isotropic transition temperature. TNI, but monotonically decrease with m at lower temperatures. We argue that these results imply large rotational fluctuations of the two halves of the dimers about the S-S bond giving rise to average bent conformations near TNI. At lower temperatures those conformations which can adapt better to the given curvature deformation in the medium are favored.

Item Type:Article
Source:Copyright of this article belongs to The American Physical Society.
ID Code:76076
Deposited On:29 Dec 2011 07:39
Last Modified:29 Dec 2011 07:39

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