Fluorinated Polyimide-Film Based Temperature and Humidity Sensor Utilizing Fiber Bragg Grating

Area of Science:

• Materials Science
• Sensor Technology
• Optoelectronics

Background:

• Development of a novel sensor system integrating a fluorinated polyimide film with a fiber Bragg grating (FBG) for environmental monitoring.
• Investigating the mechanism of moisture-induced strain transfer from the polyimide film to the FBG, resulting in a humidity-dependent wavelength shift.

Discussion:

• The hydrophobic fluoride doping in the polyimide film significantly reduces humidity hysteresis and achieves a fast moisture response time (<2 min).
• A cascaded FBG design effectively compensates for thermal crosstalk, ensuring precise temperature measurements with an accuracy of ±0.5 °C.
• The integrated sensor demonstrates a high humidity accuracy (±3% RH) and stability over extended monitoring periods (9000 min).

Key Insights:

• Fluorinated polyimide film enhances FBG sensor performance for humidity detection.
• Cascaded FBG configuration enables accurate, crosstalk-free temperature sensing.
• The developed sensor is passive, immune to electromagnetic interference, and suitable for hazardous environments.

Outlook:

• Potential applications in monitoring electro-sensitive storage environments for fuels, explosives, and chemicals.
• Further research could explore material optimization for enhanced durability and broader sensing ranges.
• Integration into wireless sensing networks for remote environmental monitoring is a promising future direction.