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Poly( N , N ‐dimethylacrylamide)‐ block ‐Poly( L ‐lysine) Hybrid Block Copolymers: Synthesis and Aqueous Solution Characterization
Author(s) -
Triftaridou Aggeliki I.,
Chécot Frédéric,
Iliopoulos Ilias
Publication year - 2010
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/macp.200900448
Subject(s) - copolymer , polymer chemistry , aqueous solution , helix (gastropod) , lysine , random coil , block (permutation group theory) , chemistry , block structure , polymer , materials science , crystallography , stereochemistry , amino acid , circular dichroism , organic chemistry , biochemistry , ecology , geometry , mathematics , welding , snail , metallurgy , biology
Four poly( N , N ‐dimethylacrylamide)‐ block ‐poly( L ‐lysine) (PDMAM‐ block ‐PLL) hybrid diblock copolymers and two PLL homo‐polypeptides are prepared via ROP of ε ‐trifluoroacetyl‐ L ‐lysine N ‐carboxyanhydride initiated by primary amino‐terminated PDMAM and n ‐hexylamine respectively. The PLL blocks render the copolymers a multi‐responsive behavior in aqueous solution due to their conformational transitions from random coil to α ‐helix with increasing pH, and from α ‐helix to β ‐sheet upon heating. The random coil‐to‐ α ‐helix transition is found to depend on the PLL length: the longer the peptide segment, the more readily the transition occurred. The same trend was observed for the α ‐helix‐to‐ β ‐sheet transition, which was found to be inhibited for short polypeptides unless conjugated with the PDMAM block.