Objects floating on the water surface is a common phenomenon in life. Controlling the floating state of an object has important applications in many fields such as ship design, mineral screening, colloidal assembly and micro and nano fabrication. In recent years, researchers have gradually revealed the role of material surface properties on the floating state. However, in the current research, it is widely believed that the state and buoyancy of an object is fixed when it floats stably.

With the support of the Ministry of Science and Technology, the National Natural Science Foundation of China, the National Research Center for Molecular Sciences in Beijing, and the Chinese Academy of Sciences, the group of Yanlin Song in the Key Laboratory of the Green Printing Institute has carried out systematic research around solid-liquid adhesion interaction and patterning in recent years, and has achieved the manipulation and precise patterning of the complex behavior of liquids (Nat. Commun. 2019, 10, 950; Sci. Adv. 2020, 6, eaay5808; Angew. Chem. Int. Ed. 2020, 59, 10535-10539; Nat. Commun. 2021, 12, 6899).

Recently, Yanlin Song's research team found that objects falling into water from different heights can exhibit different submersion depths on the water surface after stabilization, thus showing different floating states (Figure 1). In other words, the buoyancy of an object floating is not fixed, but is influenced by the falling process. Theoretical analysis shows that due to the solid-liquid adhesion, the three-phase contact line of the object after entering the water exhibits a three-phase dynamic behavior of pegging-slip-pegging, which is the fundamental reason for the different floating states of the object. Accordingly, they proposed the "floating hysteresis line" to guide the regulation of the floating state of the object. It was found that changing the loading-unloading sequence of the external force could regulate the floating state of the object (Figure 2). Subsequently, they demonstrated the application of variable floating states in the fields of interfacial catalysis, liquid evaporation, and drug release. This study has deepened the understanding of interfacial phenomena in floating processes and has important implications in related fields. The related results were recently published in the Proceedings of the National Academy of Sciences of the United States of America (https://www.pnas.org/doi/10.1073/pnas.2201665119 ). The first author of the paper is An Li, a PhD student, and the corresponding authors are Yanlin Song and Huizeng Li, associate researchers.

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