Molecular organization of polymer backbone in side-group liquid crystal polymers: ESR study of spin-labelled and spin-probed side-group liquid crystal polymers

摘要

The orientational order of a nematic liquid crystal side group copolymer aligned in a magnetic field has ben investigated using ESR spectroscopy. We find that the mesogenic groups are highly oriented parallel to the director whereas the polymer backbone appears to be randomly distributed or disordered. The EST spectra of both spin probed and spin labelled systems were recorded in their glassy nematic states at room temperature as a function of the angle between the director and the magnetic field. The spectra for the spin probe dissolved in the copolymer show that the spin probe has a high orientational order and by implication that the mesogenic side groups are highly ordered. The EST spectra of the spin labelled copolymer indicate that the orientational order for the label and so presumably the polymer backbone is zero.