Reversible demulsification and emulsification of surfactant emulsions regulated by light-responsive azo functionalized copper nanoclusters

•A novel light-responsive emulsion was prepared by introducing well-defined Cu3.•The emulsification/demulsification of prepared emulsion was achieved through the reversible self-assembly behaviors of Cu3.•The fibers on the interface could be collected and recycled for the new emulsification/demulsification process.