Fernando C. Messias Freire, Newller M. Kimura, Danilo D. Luders, Antonio J. Palangana e Manuel Simões

PHYSICAL REVIEW E – Volume: 88; Issue: 6; Article Number: 64502; DOI: 10.1103/PhysRevE.88.064502

In this work we will use digital images to compute the entropy dependence on temperature of a nematic lyotropic sample. The set of images comprehend the entire temperature range between a reentrant nematic isotropic phase transition, at a low temperature, and a usual nematic isotropic phase transition at a higher temperature. We will show that, inside the nematic phase, the image entropy profile agrees accurately with the entropy given by the Maier-Saupe model. As far as we know, this is the first time that the entropy of a lyotropic nematic phase is evaluated by this method, which introduces a way to measure their macroscopic variables. Namely, being that the entropy is a thermodynamical potential, this result implies that digital images can be used to compute mean values of nematic random variables.