Ti₃C₂T_x belongs to the family of MXenes, 2D materials with an attractive combination of functional properties suitable for applications such as batteries, supercapacitors, and strain sensors. However, the fabrication of devices and functional coatings based on Ti₃C₂T_x remains challenging as they are prone to chemical degradation by their oxidation to TiO₂. In this paper, we examine the oxidation of Ti₃C₂T_x in air, liquid, and solid media via conductivity measurements to assess the shelf life of Ti₃C₂T_x MXenes. The oxidation of Ti₃C₂T_x was observed in all the media used in this study, but it is fastest in liquid media and slowest in solid media (including polymer matrices). We also show that the conventional indicators of MXene oxidation, such as changes in color and colloidal stability, are not always reliable. Finally, we demonstrate the acceleration of oxidation under exposure to UV light.

Bendable, stretchable MXene multilayer coatings are deposited onto a wide variety of surfaces, rendering them conductive and responsive.

Quartz crystal microbalance with dissipation (QCM‐D) monitoring is a powerful tool used to sensitively examine the real‐time responses of polymer films to external responses. For example, the technique is commonly used to monitor film growth, material adsorption, thin film swelling, and ion exchange. With its rapidly expanding use, this review is intended to introduce new users to the basic principles of QCM‐D, along with practical challenges and remedies specific to polymer thin films. For both new and experienced users, specific case studies are highlighted including layer‐by‐layer assembly, electrochemical QCM‐D, swelling, sensing, and biological application. Last, the review recommends future directions for research and areas of growth.