Phase Behavior of Binary Mixtures of a Liquid Crystal and Methane

Phase diagrams of binary systems of four different liquid crystals with different polarity and CH 4 are investigated experimentally in this study. The solubility of CH 4 in liquid crystals has not been studied before. The liquid crystals used were 4-ethyl-4′-propylbicyclohexyl, 4-pentylcyclohexyl-4′-benzonitrile, 4-pentyl-4′-cyanobiphenyl, and 4-pentyloxy-4′-cyanobiphenyl. The concentration of the methane used was 0.01 wt %. The phase diagrams were studied in the temperature range of (295 to 365) K and up to 13 MPa. The phase equilibria studied were the three-phase equilibria nematic + isotropic + gas, smectic + isotropic + gas, and the two-phase equilibria isotropic + gas ↔ isotropic, nematic + isotropic ↔ isotropic, nematic ↔ nematic + isotropic, and smectic + isotropic ↔ isotropic. The main conclusion of this study is that increasing the polarity of the solvent leads to a lower solubility of CH 4 .