Ultrastable nanoemulsions in disordered and ordered states

A method of forming a biliquid material, the method comprising

• forming an emulsion comprising a plurality of droplets of a dispersed liquid phase in a continuous liquid phase;
• reducing an ionic strength of the continuous liquid phase with a surface-stabilizing material that imparts a repulsive interaction between the plurality of droplets that inhibits coalescence of the plurality of droplets;
• and
• adjusting a combination of a spatial range of the repulsive interaction, a strength of the repulsive interaction, an average droplet radius of the emulsion, a radial size polydispersity of the emulsion, a refractive index difference between the continuous liquid phase and the dispersed liquid phase, and a droplet volume fraction of the emulsion to provide the biliquid material with an ordered structurally-colored droplets structure that yields one or more structural colors when illuminated with broad-spectrum light;
• wherein:
• the dispersed liquid phase is immiscible with the continuous liquid phase;
• the surface-stabilizing material is a surfactant, a lipid, a co-polymer, or a combination of two or more thereof;
• the surface-stabilizing material is soluble in at least one of the continuous liquid phase and the dispersed liquid phase and the surface-stabilizing material adsorbs at the surfaces of the plurality of droplets;
• and
• the ordered structurally-colored droplets structure is hyperuniform, crystalline with long-range order, poly-crystalline with long-range order, non-crystalline with medium-range order, non-crystalline with short-range order, or a combination of two or more thereof;
• and
• the one or more structural colors arise from diffraction of the broad-spectrum light by the plurality of droplets.