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Homopolymers and copolymers of N ε ‐4‐phenylbenzamido‐ L ‐lysine and N ε ‐trifluoroacetyl‐ L ‐lysine: Synthesis and liquid‐crystalline properties
Author(s) -
Guillermain Céline,
Gallot Bernard
Publication year - 2002
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(200207)203:10/11<1346::aid-macp1346>3.0.co;2-z
Subject(s) - copolymer , chemistry , polymer chemistry , lysine , polymer , amphiphile , monomer , crystallography , stereochemistry , organic chemistry , amino acid , biochemistry
In order to obtain comb‐like poly‐ L ‐lysines bearing a biphenyl mesogen at the end of every repeating unit we have synthesised N ε ‐4‐phenylbenzamido‐ L ‐lysine (Kφφ) and the corresponding N ‐carboxy anydride (Kφφ‐NCA). We have homopolymerised the Kφφ‐NCA and block‐copolymerised it with the NCA of N ε ‐trifluoroacetyl‐ L ‐lysine (Kt). The structural study of homopolymers pKt and pKφφ and block copolymers pKt/pKφφ was performed by infrared spectroscopy and X‐ray diffraction. Two main types of structures were established: a bidimensional hexagonal one (H α ) where the polypeptide chains adopt an α ‐helix conformation and a lamellar smectic one (S A ) deriving from the β ‐pleated‐sheet structure of polypeptides. Homopolymers pKt and block copolymers pKt/pKφφ rich in pKt exhibit the H α structure, whereas the homopolymers pKφφ exhibit an S A2 structure, and block copolymers rich in pKφφ exhibit an S Ad structure. All the liquid‐crystalline structures were stable until the beginning of decomposition of the polymers. Hydrolysis of the pKt block of copolymers pKt/pKφφ provided amphiphilic block copolymers pK/pKφφ without modification of the structure of the mesophases.