Salt Creeping and Crystal Lifting in Ternary Droplets on Hydrophobic Substrates

Cl, over a broad substrate temperature range of 40-135 °C. Detailed experiments with water-NaCl-KCl mixtures on heated substrates reveal distinct creeping deposition patterns and crystal lifting, accompanied by systematic changes in contact angle, deposit height, and lateral footprint. Morphological analysis shows that ternary crystallization promotes elongated and hopper-type crystals that form interconnected porous networks rather than simple cubic structures. These networks act as efficient capillary pathways, sustaining liquid transport and enabling lateral redistribution of the solution, even on hydrophobic substrates. A local mass-balance between the capillary wicking flux and crystallization indicates that the extent of creeping is governed by the competition between these two processes. At elevated temperatures, this balance shifts, producing a transition from dominant creeping to a mixed regime of creeping and crystal lifting, revealing distinct temperature-dependent deposition behavior. Overall, this work proposes a generalized mechanism based on capillary-driven mass flux to explain salt creeping on hydrophobic substrates and highlights the critical role of crystal morphology in controlling liquid transport and deposit evolution during multicomponent evaporative crystallization.