Pressure sensitivity and gas desorption time are two key parameters that determine the performance of pressure sensors. Polydimethylsiloxane (PDMS) film shows potential in highly sensitive pressure sensor, however the trade-off between high sensitivity and low desorption time presents a challenge. This article proposes a novel gas pressure sensor with ultra-high sensitivity and ultra-fast desorption based on a tapered fiber coated with Polydimethylsiloxane/Metal Organic Framework (PDMS/MOF) composite film. By doping a specific MOF with amino groups into PDMS, the gas adsorption capacity can be greatly enhanced. More importantly, the gas desorption time can be greatly reduced because the large pores in MOF create fast transport channels in PDMS. Experimental results show that the gas pressure sensitivity increases with an increase of MOF doping amount, leading to shorter gas desorption times. The sensor achieves a gas pressure sensitivity of up to −228.32 nm/MPa and a gas desorption time as short as 16 s within the pressure range of 0–100 KPa with doping amount of 5 wt%. A fiber Bragg grating is connected in series for compensation of temperature crosstalk. The proposed sensor provides a good reference for integrating porous materials and optical fibers in high-sensitivity gas and biochemical sensing applications.

Soft magnetic metallic absorbents suffer from severe oxidation, reduction in permeability and deterioration in microwave absorption when exposed to high temperatures. In this study, we prepared flaky 304 stainless-steel powders as new microwave absorbents via deformation-induced ferromagnetism. The 304 stainless-steel powders showed significant increases in saturation magnetization (Ms) from 1.03 to 82.46 emu/g when their shape was changed from spheroids to flakes; the Ms further increased to 92.29 emu/g after heat treatment at 500 °C in air. The permeability of 304 alloy powders also showed an obvious increase after ball milling and remained roughly stable after heat treatment at 500 °C in air. Moreover, the permittivity exhibited a sharp decrease after heat treatment, enabling the improvement of impedance matching and microwave absorption. After heat treatment at 500 °C in air for 100 h, the simulated reflection loss of 304 stainless-steel powders with wax still showed attractive levels, giving a minimum value of −22 dB and remaining below −6 dB over 8.5–16.5 GHz at a thickness of 2 mm. Our work can help to include paramagnetic alloy systems as new microwave absorbents for working in harsh environments.