NMR studies of local dynamics in longitudinal liquid crystal polymers

3 NMR Studies of Local Dynamics in Longitudinal Liquid Crystal Polymers 

Muller et al. have used H-NMR to study molecular order and dynamics of PLCs with the general formula  

The roman numerals refer to five different polymers, deuterated at different sites in the repeating unit as indicated above. The two groups of polymers differ only in the length of the aliphatic spacer, containing ten and nine methylene units, respectively. The transition temperatures of the polyesters I-III are  

The nematic range of compounds IV-V is smaller, extending from 429 K to 543 K. 

The T and T2E relaxation times have been measured on macroscopi-cally aligned samples over a wide temperature range. The spin-spin relaxation times T2E are most sensitive to motions with correlation times of the same order of magnitude as the reciprocal of the quadrupolar coupling constant, i.e. in the range from 10 to 10 s, whereas the spin-lattice relaxation times T depend on motions with correlation times of the order of the reciprocal of the Larmor frequency, i.e. in the range from 10 to 10 s. 

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