Fig. 1. Synthesis and characterization of FC/FC endoskeletal droplets.

(A) Step-by-step emulsion synthesis process. (B) Brightfield microscope image of the endoskeletal droplets showing the unique disc-in-sphere morphology, where C₁₂F₂₆ forms the solid phase and C₅F₁₂ forms the encapsulating liquid droplet. Blue arrows show side-orientated discs, and white arrows show top-orientated discs; scale bar, 20 μm. Inset shows a fluorescent image with a side-oriented disc; scale bar, 10 μm. The discs were observed to rotate inside the droplets when disturbed by the fluid flow (movie S1). (C) At room temperature (25°C), the disc is solid (bottom right). As the droplet is heated, the disc melts (bottom left) and decreases in size until it completely dissolves at a higher temperature (top left). When cooled, the same droplet solidifies by going through a nonspherical phase (top right) and finally forming the sold disc inside the droplet; scale bar, 10 μm. (D) Diagram of T_m versus C₁₂F₂₆ content shows that the melting depends on droplet composition for two different liquid volatile species: C₅F₁₂ (filled black squares) and C₆F₁₄ (filled red circles). (E) T_c (red), T_s (green), and T_b (black) prediction for a mixture of C₅F₁₂ and C₁₂F₂₆. Note that the spinodal range and experimental temperature range (patterned black lines) do not overlap for this mixture.