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Abstract

The conformation of poly[N⁵-(2-hydroxyethyl)L-glutamine] (P(HEG-GH)), in solid state was studied by ¹³C CP/MAS NMR spectrometry and X-ray diffraction. The association of copolymers in dichloroacetic acid was investigated by following the temperature dependence of their ¹H NMR spectra, PHEG and P(HEG-GH) were prepared by the reaction of poly(benzyl γ-L-glutamate) with 2-aminoethanol and 2-aminoethanol-hydrazine mixtures, respectively. The conformation of the copolymers depends on the reaction conditions. While PHEG and the copolymers prepared with the mole ratio of hydrazine to the benzyl ester n_H/n_B = 0.25 were almost amorphous in solid state and had a random coil conformation and/or randomly oriented helices, at increased concentration of hydrazine (n_H/n_B = 0.5 and 1.0) P(HEG-GH) formed more or less ordered structure characterized by assemblies of α-helices. The copolymers prepared at n_H/n_B 3 2.0 showed features of β-sheets. The tendency of the copolymers to form associates in Cl₂CHCOOH solutions correlated well with their tendency to form ordered structures in solid state.