Fabrication of two-dimensional (2D) ordered microsphere aligned by supramolecular self-assembly of Formyl-azobenzene and dipeptide.

An azobenzene with a terminal formyl group, named as (4-[(3-Formyl-4-hydroxy)phenylazo]benzene (FHPAB)), was synthesized and used to manipulate the self-assembly of diphenylalanine (FF) molecules. Two-dimensional (2D) thin slices which are composed of ordered microspheres have been constructed through supramolecular self-assembly of FF and FHPAB. The FTIR and XPS results indicate that CN covalent bond between FF and FHPAB was generated. Hydrogen bonding and strong π-π interaction between the planar FF-HFPAB conjugates are the driving force to form the FF-HFPAB 2D thin slices. Based on the results, a possible formation mechanism of the 2D thin slices was proposed. We also found that the FF-based 2D thin slices possess superhydrophobic properties, which is therefore an extension of the range of applications of peptide assembly.