Lightweight and Mechanically Robust MXene/Polyimide/Silver Nanowire Composite Aerogels for Flexible Piezoresistive Sensors

Abstract

Two-dimensional transition-metal carbides and nitrides (MXenes) show great potential in aerogel flexible piezoresistive sensors owing to their versatile surface chemistry, high carrier mobility, outstanding metallic conductivity, and adjustable interlayer spacing under applied stress. However, the pure MXene aerogel exhibits significant plastic deformation or brittle mechanical performance due to the weak interactions between the nanosheets. Herein, a series of MXene/polyimide/silver nanowire composite aerogels with aligned lamellar microstructure are fabricated by bidirectional freezing and annealing strategies. The introduction of polyimide (PI) and silver nanowires (AgNWs) significantly improves the mechanical properties of the MXene-based aerogel. The obtained lightweight composite aerogel shows superelasticity with large reversible compressibility, excellent stability, and outstanding fatigue resistance. Moreover, owing to the highly aligned lamellar microstructure of the composite aerogel and the excellent conductivity of MXene and AgNWs, the composite aerogel exhibits great sensing performance with high sensitivity (gauge factor ∼27.8) and ultralow detection limit (<0.6 Pa). Based on the MXene/PI/AgNW composite aerogels, a series of wearable sensor applications are demonstrated.

Identification of Lung Cancer Biomarkers by Nanosensors Based on Titanium Carbide (Ti3C2Tx) MXenes

“…45 Due to several advantageous features like adjustable surface properties and tunable band gap, the Ti 3 C 2 T x -type MXene hybrid structures are investigated for sensing applications with an ultralow detection limit. 46,47 These successfully synthesized Ti 3 C 2 T x -type nanosheets exhibit ultrahigh sensitivity toward NO 2 gas at room temperature. 48 In a combined experimental and simulations work, Kim et al used a chemiresistive gas sensor to study the ultrahigh sensitivity of acetone, ethanol, ammonia, propanol, NO 2 , CO 2 , and SO 2 with (Ti 3 C 2 T x , T x : O, S, F, and OH) MXenes.…”

“…Using a DFT level simulation, the biocompatible transition-metal-based MXenes like Ti 2 CO 2 with (0001) a basal surface have high sensing propensity toward various nucleobases like DNA and RNA . Due to several advantageous features like adjustable surface properties and tunable band gap, the Ti 3 C 2 T x -type MXene hybrid structures are investigated for sensing applications with an ultralow detection limit. , These successfully synthesized Ti 3 C 2 T x -type nanosheets exhibit ultrahigh sensitivity toward NO 2 gas at room temperature …”