Tough and Antifreezing MXene@Au Hydrogel for Low-Temperature Trimethylamine Gas Sensing

Abstract

Trimethylamine (TMA) is one of the important chemical indexes to judge the freshness of marine fish. It is necessary to develop a low temperature TMA sensor to help the monitoring and prediction of the quality of marine fish in cold chain. Herein, a flexible low temperature TMA gas sensor featuring antifreezing and superior mechanical properties was developed based on the Au nanoparticle-modified MXene (MXene@Au) composite. MXene@Au was synthesized and then polymerized with a hydrogel composed of acrylamide (AM), N,N′-methylenebisacrylamide (BIS), sodium carboxymethyl cellulose (CMC), and EG, and the resultant MXene@Au hydrogel was found to exhibit excellent antifreezing performance even at extremely low temperature as well as high tensile strength, ultrastretchability, and toughness, which enabled an efficient gas sensing platform for TMA detection at low temperature. The TMA sensing properties of the flexible MXene@Au DN hydrogel sensor at 25 °C and a low temperature of 0 °C were studied, and a linear relationship between TMA sensitivity and concentration was built. The excellent sensing properties were maintained even under deformation. The application of the MXene@Au DN hydrogel sensor in detection of fish freshness at 0 °C was investigated. The result indicated the potential application of the flexible MXene@Au DN hydrogel gas sensor in dynamic quality monitoring and prediction of marine fish products during its transportation and storage in the cold chain.

d-Band Center Optimization of Ti3C2Tx MXene Nanosheets for Ultrahigh NO2 Gas Sensitivity at Room Temperature

“…During the recovery process, the NO 2 molecules gradually desorb from the MXene surface, returning the resistance of MXene to its initial value. Typically, the sensor response is defined as the relative change in the electrical resistance or current of the sensor when exposed to the target gas, compared to the baseline resistance or current, i.e., (Δ R / R 0 (%) or Δ I / I 0 (%)). − In this work, the sensing response can be described as follows: Response = normalΔ I I 0 100 % = false| I normalg − I 0 false| I 0 100 % where I g and I 0 are the current values of the sensor exposed to the target gas and air, respectively. Figure b is the static response data of Figure a with respect to the NO 2 concentration.…”

Significant Roles of Ions in Enhancing and Functionalizing Anisotropic Hydrogels

“…A great issue for state-of-the-art ion sensors used outdoors is their adaptability to harsh natural environments, leaving an open question of whether ion sensors are able to remain useful under harsh conditions such as high and low temperatures. − That is, advanced ion sensors are often required to show water retention capability and antifreezing properties. A solar simulator and a refrigerator are used to simulate the harsh environments for the Aniso-Ca 1.5 2+ hydrogel (Figure S17), with the isotropic hydrogel for comparison.…”

Flexible Synergistic MoS2 Quantum Dots/PEDOT: PSS Film Sensor for Acetaldehyde Sensing at Room Temperature

“…The gas-sensing properties of the sensors were detected in a static test system at room temperature (25 ± 2 °C; 30 ± 10% RH), which was composed of a test chamber, an external power source, a fixed-value resistance, and a digital multimeter with data analyzer, as reported in our previous work . Briefly, the concentration of the tested gas was obtained by a static liquid gas distribution method.…”

“…The gas-sensing properties of the sensors were detected in a static test system at room temperature (25 ± 2 °C; 30 ± 10% RH), which was composed of a test chamber, an external power source, a fixed-value resistance, and a digital multimeter with data analyzer, as reported in our previous work. 22 Briefly, the concentration of the tested gas was obtained by a static liquid gas distribution method. That is, the liquid was evaporated into its gaseous state in a container, and a certain volume of the evaporated gas was injected into the test chamber to prepare the designed gas concentration.…”