Synthesis And Characterization Of Main Chain Supramolecular Liquid Crystals Through Intermolecular Hydrogen-bonding

Synthesis for supramolecular self-assembly have the advantages of high yield and environmental benignity. Supramolecular liquid crystalline complexes based on non covalent interaction. Supramolecular liquid crystalline which were synthesized through Hydrogen-bonding self-assembly have characteristics of bad stability relative to covalent interaction. Moreover, they have a high response degree following environmental change and response rapidly to the temperature, their potential applied value can be found when the temperature was controlled strictly.The present paper deals with the synthesis of dicarboxylic aid component monomer: 4-(6-(4-carboxyphenoxy)-6-oxohex-l-en-2-ylperoxy)benzoic acid(M1),4-(10-(4-carboxyphenoxy)-10-oxodec-1-en-2-ylperoxy)benzoic acid(M2),4-(2-(6-(2-(4-carboxyphenoxy)ethoxy)-6-oxohex-1-en-2-ylperoxy)ethoxy)benzoic acid(M3),4-(2-(10-(2-(4-carboxyphenoxy)ethoxy)-10-oxodec-1-en-2-ylperoxy)ethoxy)benzoic acid (M4). Dipyridinium component monomer:Ppy(N1), pyridin-4-y15-(pyridin-4-ylperoxy)hex-5-enoate(N2). In the paper, two series main chain supramolecular Liquid Crystals are obtained according to the self-assembly between dicarboxylic aid component and dipyridinium component when the molar ratio was 1:1. The structures and properties of dicarboxylic aid component monomer and main chain supramolecular in the paper were tested and analyzed by FT-IR, polarizing optical microscopy(POM) and differential scanning calorimeter (DSC),and Hydrogen-bonding of main chain supramolecular Liquid Crystals was investigated by Temperature-dependant FT-IR.According to the result, the series of main chain supramolecular compounds CLSM1 synthesized exhibited excellent liquid crystalline properties. Melting point and clear point of the supramolecular liquid crystals decreased with the increasing of soft segment of the molecules. And the mesogenic regions also changed. No evidence to see that the supramolecular compounds CLSM2-1,2 in series of CLSM2 are liquid crystals. While CLSM2-3,4 are typical nematic liquid crystals.Temperature-dependant FT-IR was used to study the dicarboxylic acid monomer and main chain supramolecular liquid cystals. The result showed the frequency of stretching vibrations of hydroxyl group of carboxylic acid red-shifted to low wave number, while the change was small with only about a few to about a dozen wave numbers. The absorb peak around 2480cm-1 of hydrogen bond between carboxylic acid and pyridine(N---HO-C=O)blue-shifted to high wave number with the increasing of temperature. While there was no obvious change with the absorb peak around 1900 cm-1.The obvious influence of the absorb peak of hydrogen bond between carboxylic acid and pyridine on the critical ambient temperature provided high potential practical value for these series of supramolecular liquid cystals.