Complexation reaction of poly(L‐glutamic acid) with Cu ions and the effect of helix‐coil transition of the polymer chain

The complexation reaction of poly( L ‐glutamic acid) ( 1 ), with Cu ions in aqueous solution was studied by pH titration, spectroscopy, circular dichroism measurements and solution viscosity. The adsorption of Cu ions depended on the secondary structure of 1; 1 adsorbed Cu ions when its degree of neutralization was higher than 0,6. Thus, this phenomenon was attributed to the helix‐coil transition of 1 . It was cleared that the helical structure was retained because of chelating between Cu ions and carboxyl groups of the side chain of 1 . The formation of the Cu/ 1 complex was compared with that of the Cu/poly(acrylic acid) complex ( 2 ).