Transient Structural Coloration During Dewetting Transition of Water‐In‐Oil‐In‐Water Droplets

Structural coloration based on microscale concave interfaces provides a versatile method for generating iridescent colors, yet it remains challenging to achieve in water-based droplet systems. Here, it is reported a transient structural coloration process during the dewetting transition of water-in-oil-in-water emulsion droplets. It is demonstrated that the total internal reflection (TIR) and structural coloration are restricted to a narrow operational window, primarily dictated by droplet size ratios and dewetting morphologies. These findings deepen the understanding of structural coloration in complex droplet systems, providing valuable insights for designing and controlling dynamic optical systems in adaptive photonic devices and responsive optical technologies.