Characterization of a hydrogen bonded liquid crystal homologous series: Detailed FTIR studies in various mesophases

Novel linear hydrogen bonded liquid crystal homologous series has been synthesized and characterized. Hydrogen bond is formed between hydroxy benzaldehyde and various benzoic acids which are varying from pentyl to dodecyl alkyloxy carbon numbers. Synthesized complexes are characterized by FTIR for inferring the formation of hydrogen bonds. Polarizing microscopy and DSC studies reveal various mesophases and their corresponding transition temperatures along with respective enthalpy values. Tilt angle and helix in Smectic C phase have been experimentally elucidated for most of the mesogens. A new technique for the temperature dependent FTIR studies has been proposed. The spectral results obtained by this technique are in good agreement with the conventional method. These FTIR studies bestow information about shifting and occurrence of new peaks in various mesophases thus enriching the knowledge on the chemical molecular environment of the mesogen.