Highly Stable Cross‐Linked Cationic Polyacrylamide/Ti₃C₂T_x MXene Nanocomposites for Flexible Ammonia‐Recognition Devices

Abstract

Although ammonia gas sensor research has been developed for a long time, room temperature flexible ammonia gas sensors with high sensitivity and selectivity are still hot research topics. 2D transition metal carbides and nitrides (MXenes) have combined their versatile surface chemistry and high metal conductivity to show their enormous sensing potential. Herein, developing a room temperature nanocomposite based on 2D MXenes materials and cationic polyacrylamide (CPAM) with high gas response and flexibility targeting the construction of high‐performance ammonia sensors is focused on. Thanks to the hydrogen bond composition, ohmic contact with the interdigitated electrodes, and excellent mechanical properties, the CPAM/Ti3C2Tx‐based ammonia sensors exhibit high ammonia selectivity, faster response–recovery rate (12.7/14.6 s), excellent flexibility, and long‐term mechanical stability at room temperature. The synthesis of the CPAM/Ti3C2Tx nanocomposites offers a lasting inspiration for developing high‐performance flexible gas sensors.

Emerging MXene–Polymer Hybrid Nanocomposites for High-Performance Ammonia Sensing and Monitoring

“…During wet spinning, an aqueous solution of precursors is blended through centrifugation to obtain MXP-NCs. Zhao et al [ 61 ] fabricated Ti 3 C 2 T x /CPAM NC by stirring the aqueous solution of Ti 3 C 2 T x and CPAM through centrifugation. However, in solution blending, two different precursor solutions (which are mutually soluble) are used [ 39 ].…”

“…Wang et al [ 56 , 57 ] fabricated a Nb 2 CT x /PAN chemiresistor by spray coating prepared MXP-NCs over PI substrate (with Au interdigitated electrodes) in two different reports. However, Zhao et al [ 61 ] used PET substrate with interdigitated silver electrodes to fabricate the CPAM/Ti 3 C 2 T x based NH 3 sensor. Few reports on the fabrication of NH 3 sensors suggest dispersing polymeric systems such as PAP or its composites such as polyaniline–silver nanocomposite in m-cresol on glass substrates [ 3 , 69 ].…”

“…Jin et al [ 65 ] observed significantly enhanced interlayer separation between Ti 3 C 2 T x nanosheets by introducing PEDOT: PSS. Zhao et al [ 61 ] observed the formation of a multilayer Ti 3 C 2 T x structure with different layers glued by CPAM. Similar results were obtained for M 2 X 2 T x -P NCs by Wang et al [ 56 ], utilizing in situ and ex situ synthesis approaches in distinct reports.…”

“…MXP-NCs are an example of engineered material with mechanical properties, which possess significant mechanical flexibility due to polymer and enhanced mechanical strength in terms of tensile strength, Young’s modulus, and less crack formation due to the presence of MXene [ 38 ]. Zhao et al [ 61 ] reported Ti 3 C 2 T x /CPAM NC flexibility for NH 3 sensing with a bending test. It is revealed that the NCs are strong and flexible due to the binding action of CPAM among Ti 3 C 2 T x layers.…”

Flexible MXene‐Based Composites for Wearable Devices

“…Moreover, the hybrid fibers with satisfied mechanical strength could be woven into an experimental clothing, indicating their good weavability and potential as wearable devices. Zhao et al [54] Furthermore, water vapor is a special kind of gas, and MXene-based composites had been reported as humidity sensors as well due to the changes during hydration/dehydration process of water molecules. A flexible and multifunctional MXene/AgNWs-decorated composite silk textile was developed by a vacuum-assisted layer-by-layer method.…”