Construction of a New Supramolecular Polymer by Hierarchic Integration of Supramolecules

Abstract

Multiple H-bonding has been observed as a β-sheet structure in the cast films of the peptide-containing amphiphiles. These amphiphiles produce a self-supporting transparent film, but they are extremely brittle. This result means that another interaction, which immobilizes the β-sheets, will be needed for improving the mechanical strength of the supramolecular film. Thus, we attempted to use the side chains of the peptide part. Because the side chains of the adjacent amino acid residues locate in opposite directions across the β-sheet plane, the side chains could interlock with counterparts of the other β-sheet planes. This specific interdigitated structure should fasten the β-sheet planes when the peptide part contains at least three consecutive leucine. We prefer to use this action leucine fastener. The leucine fastener will never be formed if a β-sheet structure is absent. Emphasis is placed on this hierarchy. In our case, monomeric units self-assembled into a supramolecule formed a β-sheet assemblage. The β-sheet assemblages were integrated by the leucine fastener, and finally produced a supramolecular polymer. We demonstrated here the hierarchic integration of supramolecular monomers, and described the formation of a self-supporting elastic film, in which repeating units were linked by non-covalent bonds.