In Situ Tracking of Wetting‐Front Transient Heat Release on a Surface‐Mounted Metal–Organic Framework

Abstract Transient heat generation during guest adsorption and host–guest interactions is a natural phenomenon in metal–organic framework (MOF) chemistry. However, in situ tracking of such MOF released heat is an insufficiently researched field due to the fast heat dissipation to the surroundings. Herein, a facile capillary‐driven liquid‐imbibition approach is developed for in situ tracking of transient heat release at the wetting front of surface‐mounted MOFs (SURMOFs) on cellulosic fiber substrates. Spatiotemporal temperature distributions are obtained with infrared thermal imaging for a range of MOF‐based substrates and imbibed liquids. Temperature rises at the wetting front of water and binary mixtures with organic solvents are found to be over 10 K with an ultrafast and distinguishable thermal signal response (<1 s) with a detectable concentration limit ≤1 wt%. As an advancement to the state‐of‐the‐art in trace‐solvent detection technologies, this study shows great prospects for the integration of SURMOFs in future sensor devices. Inspired by this prototypal study, SURMOF‐based transient heat signal transduction is likely to be extended to an ever‐expanding library of SURMOFs and other classes of surface‐grafted porous materials, translating into a wide range of convenient, portable, and ubiquitous sensor devices.