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od 2020-09-20

Title: 1H NMR spectra of 5CB liquid crystal and 5CB-MCM heterogeneous system

Source: Proceedings of SPIE - XVI International Conference on Spectroscopy of Molecules and Crystals

Year : 2004

Abstract:

It is shown that, in the 1H NMR spectra of 5CB, the splitting of proton bands is the result of the dipole-dipole interaction. Using the value of the splitting of the 1H bands, we determined the order parameters S for some fragments of 5CB molecules in the nematic phase. It is found that the values of S for the biphenyl core are twice greater than that for alkyl radical, which is the evidence for different dynamics of these structure fragments. From the analysis of the form of bands in the 1H spectra in the hetereogeneous system 5CB-MCM, we showed that, in the temperature range of the existence of the nematic and crystal phases of bulk 5CB, there is no ordering of these molecules in the channels of MCM. This is caused by the appearance of defects in the liquid crystal ordering due to the interaction of some part of the LC molecules with the active centers of the surface of MCM channels.

DOI: 10.1117/12.569807   (Pobrane:  2021-01-11)