The Role of Water in Mediating Interfacial Adhesion and Shear Strength in Graphene Oxide

Graphene oxide (GO), whose highly tunable surface chemistry enables the formation of strong interfacial hydrogen-bond networks, has garnered increasing interest in the design of devices that operate in the presence of water. For instance, previous studies have suggested that controlling GO’s surface chemistry leads to enhancements in interfacial shear strength, allowing engineers to manage deformation pathways and control failure mechanisms. However, these previous reports have not explored the role of ambient humidity and only offer extensive chemical modifications to GO’s surface as the main pathway to control GO’s interfacial properties. Herein, through atomic force microscopy experiments on GO–GO interfaces, the adhesion energy and interfacial shear strength of GO were measured as a function of ambient humidity. Experimental evidence shows that adhesion energy and interfacial shear strength can be improved by a factor of 2–3 when GO is exposed to moderate (∼30% water weight) water content. Furthermore...