DiblockTriblock Structural Transition and Sol-Gel Transition of PeptidePEG Diblock Copolymer Having a Terminal Terpyridine Group Induced by Complexation with Metal Ion

Abstract EN

Terpyridine-polyethyleneglycol-block-polyleucine block copolymer (tpy-PEG-PLeu) was synthesized by a ring-opening polymerization of L-leucine N-carboxyanhydride.

The copolymer complexed with Fe2+ ion and its aqueous solution showed a purple color as a result of the complexation.

This complexation caused the diblock/triblock structural transition of the copolymer.

The change of the aggregation behavior caused by the structural transition was observed by a dynamic light scattering apparatus.

The diblock tpy-PEG-PLeu copolymer formed a micelle in the aqueous solution.

On the other hand, the triblock-type copolymer, after the complexation, formed the micelle structures and huge aggregates, which is considered to be a network structure.

The complexation of the diblock tpy-PEG-PLeu copolymer with Fe ion is consequently considered to be a trigger of the gelation.