Resumo

GARCIA-SANCHEZ, E; CASTANEDA-RAMIREZ, C.H.  e  CERVANTES-VIRAMONTES, J.M.. Effect of Potential Range in Pressure-Temperature Behavior in Isotropic-Nematic Transition of 4-4'-Bis(Ethyloxy) Azoxybenzene (P-Azoxyphenetole, Pap), 4-Pentyl-4'-Cyanobiphenyl (5cb), P-Methoxybenzydidene-P-N-Butylaniline (Mbba) and P-Ethoxybenzylidene-P-N-Butylaniline (Ebba). Ing. invest. y tecnol. [online]. 2011, vol.12, n.2, pp.157-163. ISSN 2594-0732.

In this work we employed the Density Functional Theory (IPCM model) to calculate molecular volume and k, and the perturbation theory proposed by García-Sánchez et al. (2002) to predict phase diagram and experimental behavior pressure-temperature for isotropic-nematic transition of 4-4'-bis(ethyloxy)azoxybenzene (p-azoxyphenetole, PAP), 4-pentyl-4'-cyanobiphenyl (5CB), p-methoxybenzydidene-p-n-butylaniline (MBBA) and p-ethoxybenzylidene-p-n-butylaniline (EBBA) at 1 atm. If during the theoretical prediction bigger potential values of potential range of square well (λ > k) are considered in the theoretical model, it is possible to get better prediction of the experimental behavior. The above mentioned is according with the theoretical formulation of the Second Order Perturbation Theory since Ponce-Renon approximation is included.

Palavras-chave : convex peg; phase transitions; liquid crystal; IPCM model; isotropic-nematic; density functional.

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