GIBBSIAN ADSORPTION OF VOLATILE ORGANIC-COMPOUNDS AT THE NEMATIC LIQUID-CRYSTAL GAS INTERFACE

The behavior of the surface tension sigma of a nematic liquid crystal p,p'-methoxyethoxyazoxybenzene (MEAB) exposed to the vapors of volatil e organic compounds having various molecular structures (n-alkanes, n- alkanols, meta- and para-xylenes, and pyridine) was studied. Measureme nts were performed by the pendant drop technique in a wide temperature interval (100 - 165 degrees C). In this temperature range, the molecu les of all organic compounds studied (except for ethanol in the sub-tr ansition region) exhibit surface activity and reduce the sigma value o f MEAB, The temperature dependences of sigma for the nematic MEAB phas e have maxima at the point of phase transition to isotropic phase. At high vapor concentrations of n-alkanols in the gas phase, the maximum shifts to lower temperatures.