An Undergraduate Experiment on Photocatalysis-Driven Wetting Transitions for Liquid Marble Coalescence and Microchemical Reactions

This laboratory experiment offers undergraduates a hands-on exploration of surface wettability, photocatalysis, and their application in initiating microchemical reactions. Students observed how selected UV irradiation induced a wettability transition from hydrophobic to hydrophilic and explored the photocatalytic degradation mechanism driving this phenomenon. This localized transition at the contact points between two liquid marbles triggers their coalescence, mixing the encapsulated reactants and initiating a microchemical reaction. This experiment advances beyond traditional static wettability measurements by demonstrating a dynamic application of the concept. It aims to deepen students’ understanding of surface chemistry and develop their skills in applying photocatalysis to control microreactions, thereby fostering an appreciation for interdisciplinary science. The experiment is suitable for second- or third-year undergraduate physical chemistry or materials chemistry laboratories.