Inverse gas chromatography study of the thermodynamic behaviour of thermotropic low molar mass and polymeric liquid crystalsElectronic supplementary information (ESI) available: Partial molar enthalpies, excess enthalpies, entropies and excess entropies for hydrocarbon probes in liquid crystals. See http://www.rsc.org/suppdata/cp/b2/b202173k/

Abstract

We report measurements of activity coefficients and derived excess partial molar enthalpies and entropies of mixing for 17 hydrocarbon probes in three low molar mass liquid crystals as well as a polymeric version containing the same mesogenic group. Values were obtained in the isotropic liquids and in N, SmA, SmC, and N* mesophases. The results are interpreted in terms of a qualitative, descriptive model accounting for the various contributions to the energetics and the entropic effects of probe-LC interactions. The behaviour of the LC polymer was found to be determined largely by the interactions with the mesogen while the polymer backbone had a relatively minor effect.

Interactions of Solvents with Low Molar Mass and Side Chain Polymer Liquid Crystals Measured by Inverse Gas Chromatography

“…Values for the branched alkanes are also higher than the linear isomers. Previous consideration 23 of the enthalpies and entropies of solution for these systems suggested that the longer chain alkane probes are able to undergo stronger interactions with the liquid crystal but suffer from a greater constraint in the conformations they can adopt and that the branched isomers interact more weakly and are subject to lesser restriction on mobility in the mesophases.…”

“…This paper presents work aimed at quantifying interactions in LC containing materials. In a previous publication 23 the behavior at infinite dilution of several systems was discussed in terms of the probe activity coefficients. In this paper, interaction parameters for two low molar mass alkoxybiphenyl LC's and a side chain LC polymer bearing the same mesogen are reported and interpreted in terms of the chemical structures of the compounds involved.…”

IGC studies of binary cationic surfactant mixtures

“…IGC has been employed for the characterisation of the thermodynamic behaviour of liquid crystals [24] through the activity coefficients, enthalpies and entropies involved in the dissolution process. Price and Shillcock [25] reported a study of the behaviour of siloxane-cianobiphenyls with low molar mass. They also determined activity coefficients and interaction parameters of these liquid crystals [26].…”

A new liquid crystal of considerable value for the separation of closely related solvents by gas chromatography

“…Liquid crystals have found extensive use as the stationary phase in gas chromatography. Liquid crystalline stationary phases are useful for separating isomers having similar boiling points, which are very difficult to separate using classical stationary phases [5][6][7][8][9][10].…”