Abstract: Surface chemistry permeates various aspects of our daily lives, from the natural phenomenon of the “lotus leaf effect” to the functionalities of specialized industrial products like waterproofing, anti-freezing, and anti-fouling coatings. While these phenomena may seem commonplace and straightforward, they harbor intricate principles of interfacial science. In this experiment, we employ a layer-by-layer self-assembly technique to deposit a hydrophilic coating composed of plant polyphenol tannic acid (TA) and iron (Fe(III)) coordination complex onto the surface of a melt-blown fabric membrane. Subsequent oxidation of catechol groups using sodium periodate (NaIO₄) facilitates the fixation of the polyphenol-metal coordination complex network at the fabric interface, thereby achieving a transition from hydrophobic to hydrophilic modification. Finally, we demonstrate the efficacy of the modified melt-blown fabric membrane in oil-water separation processes. Through this endeavor, we not only showcase the modification process of materials and the resulting property alterations but also delve into the underlying physical and chemical principles layer by layer. The reagents utilized in this educational experiment are environmentally friendly, facilitating simple operation, offering aesthetic appeal, and encouraging interaction. Moreover, the modified membrane boasts recyclability advantages. Employing a gradient approach to science communication, we elucidate the principles and essence behind these phenomena in a comprehensible manner, enabling the public to appreciate the magic and beauty of surface chemistry while acquiring knowledge. This experiment holds promise not only for popular science dissemination and classroom teaching but also for its excellent application prospects.

Key words: Surface chemistry, Wetting inversion, Membrane materials, Metal-polyphenol coordination complex, Oil/water separation