Tunable Structural Coloration in Eccentric Water-in-Oil-in-Water Droplets

Area of Science:

• Materials Science
• Optics
• Colloid Science

Background:

• Structural colors offer advantages over chemical pigments, including fade resistance and eco-friendliness.
• Current methods for generating structural colors often lack tunability or are unsuitable for aqueous systems.

Purpose of the Study:

• To demonstrate tunable structural coloration in colorless water-in-oil-in-water double emulsion droplets.
• To investigate the role of shell thickness and core-shell eccentricity in forming iridescent structural colors.
• To explore the responsiveness of these droplet-based structural colors to environmental stimuli.

Main Methods:

• Utilized total internal reflection and interference at microscale concave interfaces.
• Employed experimental studies and simulations to analyze droplet structures.
• Investigated responses to osmotic pressure, temperature, magnetic fields, and light composition.

Main Results:

• Tunable iridescent structural colors were achieved in specific water-in-oil-in-water double emulsion droplets.
• Eccentricity and thin shell thickness were identified as critical parameters for color formation.
• Structural colors demonstrated sensitivity to various environmental stimuli.

Conclusions:

• Eccentric, thin-shelled double emulsion droplets are a viable platform for generating tunable structural colors.
• These droplet-based structural colors offer a responsive and eco-friendly alternative to traditional pigments in aqueous systems.
• This research expands the application of droplet-based structural coloration to diverse aqueous environments.