High‐Contrast Colorless‐to‐Colored Thermochromic Materials

<0), due to self-assembly and phase segregation of CD molecules from PCMs, preventing their interaction with the dye. Instead, when ΔC≥0, the CD solubilizes in PCMs, developing the color of the co-dissolved dye. The rule is extendable to several leuco dye families (lactams, lactons, fluorans) and acid PCMs, fostering a tunable hot state color palette and transition temperature. The target transition is also preserved in structured mixtures (solid lipid particles), granting for the preparation of polymer composites and screen-printed thermochromic patterns, of interest for sensors and invisible security inks.