STRUCTURE AND MOBILITY OF POLY(GAMMA-N-ALKYL-L-GLUTAMATE)S IN THE SOLID AND LIQUID-CRYSTALLINE STATES AS STUDIED BY NMR-SPECTROSCOPY

C-13 CP/MAS NMR and pulse H-1 NMR experiments were carried out for pol y(gamma-n-alkyl-L-glutamate)s (PALGs) in which the number of carbon at oms of the alkyl side-chains was either odd or even, in order to eluci date the conformation, crystal structure and dynamics of the polymers. From these results, it is found that the main-chain takes an alpha-he lix conformation irrespective of the alkyl side-chain length. However, n-alkyl side-chains crystallize with an all-trans zigzag conformation for PALGs when the number of carbon atoms in the n-alkyl side-chains is more than 14. Further, from the pulse H-1 NMR results, it is found that the H-1 spin-spin relaxation time (T2) of the side-chains increas es abruptly with an increase in temperature for PALGs with a carbon nu mber of more than 10, which is evidence for the solvent-like nature of the side-chains in the liquid crystalline phase.