Abstract
A novel series of side-chain liquid crystalline copolysiloxanes containing [S]-1-(2-naphthyl) ethyl 6-[4-(10-undecen-1-yloxy) biphenyl-<svg style="vertical-align:-0.0pt;width:12.4375px;" id="M1" height="17.7125" version="1.1" viewBox="0 0 12.4375 17.7125" width="12.4375" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(.017,-0,0,-.017,.062,17.65)"><path id="x34" d="M456 178h-96v-72q0 -51 12.5 -62.5t72.5 -16.5v-27h-256v27q65 5 78 17t13 62v72h-260v28q182 271 300 426h40v-407h96v-47zM280 225v295h-2q-107 -148 -196 -295h198z" /></g> <g transform="matrix(.012,-0,0,-.012,8.225,9.488)"><path id="x2032" d="M227 744l-123 -338l-31 15l73 368q12 3 41.5 -8t36.5 -20z" /></g> </svg>-carbonyloxy]-2-naphthoate mesogenic and 4-biphenyl <svg style="vertical-align:-0.0pt;width:12.4375px;" id="M2" height="17.7125" version="1.1" viewBox="0 0 12.4375 17.7125" width="12.4375" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(.017,-0,0,-.017,.062,17.65)"><use xlink:href="#x34"/></g> <g transform="matrix(.012,-0,0,-.012,8.225,9.488)"><use xlink:href="#x2032"/></g> </svg>-allyloxybenzoate mesogenic side groups in the backbone and side chains liquid crystalline copolymers were prepared and evaluated as possible stationary phases for gas chromatography capillary columns. All copolymers display enantiotropic cholesteric phases. These mesomorphic polysiloxanes specimens with the widest temperature range were used as the stationary phase in a gas chromatography capillary column, and it showed good thermal and physical stability, excellent chemical inertness, and unique separation properties for polycyclic aromatic compounds. These cholesteric LC copolysiloxane stationary phases show much better separation effect for the polycyclic aromatic compound than those of the nematic and smectic LC copolysiloxanes.
Highlights
Increasing requirements on analyses of isomeric compounds and the problems encountered in their separation necessitate a study of more efficient systems which exhibit a high selectivity
The interaction mechanisms are different with liquid crystals, the stereoselective properties are so important that it is desirable to deal with their potential use in gas chromatography (GC)
Polymer P3 exhibited the widest range of temperatures for the cholesteric mesophase, a glass transition at 53.2◦C, and a phase transition form cholesteric to isotropic at 234.8◦C based on differential scanning calorimeter (DSC) heating scan
Summary
Increasing requirements on analyses of isomeric compounds and the problems encountered in their separation necessitate a study of more efficient systems which exhibit a high selectivity. Attention is focused on the use of substances with oriented molecules that permit selective separations; these properties are exhibited by, for example, inclusion of some compounds and liquid crystals. A liquid crystal stationary phase separates analytes based upon differences in solute molecular shape, with the anisotropic packing behavior of liquid crystalline materials permitting the separation of isomers based on their individual molecular geometries (length-to-breadth) [6]. In order to take advantage of all these properties, we selected polysiloxane as the polymer backbone and 11 methylene units as the spacer, and [S]-1-(2-naphthyl)ethyl 6-[4-(10-undecen-1-yloxy) biphenyl-4-carbonyloxy]-2-naphthoate as the mesogen. These materials tend to form cholesteric mesophases over a broad temperature range Among these polymers, we selected P3, which shows the widest temperature range of cholesteric phase, to fabricate the capillary column stationary phase.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
