Pie charts showing three phases, two phases and one phase, based on the proportions of the constituents. A–D show three, two and bi-continuous phase emulsions. E: One phase of rosemary oil in water nano-emulsion (REO/NE). The green, blue and yellow slices represent the rosemary oil, distilled water and the mixture (2:1) of tween 80 to span 20, respectively. F: Turbidity – temperature curve of the resultant one-phase REO/NE showing the changes in the opacity of the formula at different temperatures. Data are presented as mean ±SD (n = 3).