Vapor-stimuli shape transformation cycles of assembled dipeptide film

Abstract

Stimuli-responsive peptide assembly has an excellent ability to change morphology, property or functions through response to appropriate external stimuli owing to the existence of noncovalent connections between their building blocks. However, study on vapor-responsive dipeptide assembly is still desirable for the development of peptide structure formation and regulation. Here, we reported the reversible cycles of vapor-responsive shape transformation based on diphenylalanine (FF) film. We prepared an amorphous FF film via dip-coating approach. With different vapor-stimuli (HCl, NH3 or H2O), this amorphous film could transform to different morphology, such as grain-like, flake-like shape, or fibers with time increasing·H2O vapor can change hydrophobic /hydrogen-bonding interactions, while HCl and NH3 vapor can change the proton/deproton behavior of FF molecules and all of them may participant the arrangement of molecular packing, inducing the shape transformation. The shape transformation cycle may offer a concise and easy-controllable strategy for peptide-based assemble materials. In addition, the vapor-stimuli shape transition also changed the hydrophilicity/hydrophobicity of the film surfaces, which may have potential applications in the area of hydrophobic coatings in further research.