Improving Anti-Humidity Property of a SnO₂-Based Chemiresistive Hydrogen Sensor by a Breathable and Hydrophobic Fluoropolymer Coating

Abstract

Metal-oxide-based chemiresistive hydrogen sensors exhibit high sensitivity, long-term stability, and low cost and have been extensively applied in safety monitoring of H 2 . However, the sensing performances are dramatically affected by the water vapor, resulting in reduced response value and increased response/recovery time. To improve the anti-humidity property of sensors, coating the breathable and hydrophobic membrane on the surface of the sensing film is an effective strategy. In this work, the poly[4,5-difluoro-2,2bis(trifluoromethyl)-1,3-dioxole-co-tetrafluoroethylene] (Teflon AF-2400) was dip-coated on the surface of SnO 2 in a commercial hydrogen sensor (TGS2615) as a breathable and hydrophobic membrane. For safety, He instead of H 2 was used to test the gas permeability of membranes. The Teflon membrane shows a high He permeability of up to 40,700 Barrer and an excellent He/H 2 O selectivity of 99. Moreover, Teflon shows high processability to form a defect-free coating on the rough surface of the sensing film and high chemical stability under the operando condition of the sensor. Thus, the Teflon-modified sensor possesses excellent selectivity with a value of 5, and the resistance is stable at 10,554 ± 3% Ω for 20 days in 80% RH. The modified sensor shows an improved anti-humidity property with a 75% response to 200 ppm H 2 at 80% RH and has a low coefficient of variation value of 7.23% that shows advances than other reported sensors modified by coatings. The commercially available Teflon and the simple coating technology make the strategy easily scale up and show promising applications.

In situ laser-assisted decoration of Au nanoparticles on 3D porous graphene for enhanced 2-CEES sensing

“…Surface modification of the gas sensor with breathable hydrophobic coatings can also greatly negate the interference from humidity. 19,54 LIG/Au-0.1 M was continuously tested for five cycles at 80 1C with 1.0 ppm 2-CEES, and the result in Fig. 5(c or magnetron sputtering of Au.…”

“…Surface modification of the gas sensor with breathable hydrophobic coatings can also greatly negate the interference from humidity. 19,54…”

Excellent-Moisture-Resistance Fluorinated Polyimide Composite Film and Self-Powered Acoustic Sensing

“…Polyimide (PI) is widely used in electrical, aerospace, microelectronics, and other fields because of its excellent dielectric properties, mechanical properties, and thermal stability, and it is also a common electronegative material for triboelectric nanogenerators (TENGs). − Some works enhanced the triboelectric performance of the PI film by fluorination and achieved excellent results. , However, the effect of humidity on the triboelectric performance of the PI film has also not been explored. Teflon AF is an amorphous fluoropolymer with excellent optical transparency and breathability, and the low surface energy and excellent charge injection property may provide solutions to the above problem. − …”

Enhanced Acetone-Sensing Properties of Pt-Decorated In2O3 Hollow Microspheres Derived from Pt-Embedded Template

“…Yao et al presented a comprehensive engineering review of metal–organic framework (MOF)-derived hollow MOS semiconductor heterostructures for gas sensor applications, focusing on the advantages s and representative application examples for toxic gas . Unfortunately, MOS-based sensors have sluggish response/recovery rates, limited selectivity, and inadequate detection limits at high working temperatures (250–500 °C), which contradicts most practical applications. , For acetone sensors, one very important issue is the low detection limit and the stability at high humidity, which has been emphasized in numerous acetone-related studies and reviews. − This is the main reason why acetone exhaled breath detection has not yet reached the clinical stage. Therefore, various strategies to modify metal oxides have been reported to improve the performance of acetone detection.…”