PDMS-coated fiber volatile organic compounds sensors

Area of Science:

• Optoelectronics
• Chemical Sensing
• Materials Science

Background:

• Volatile organic compounds (VOCs) pose environmental and health risks, necessitating effective detection methods.
• Interferometric fiber sensors offer high sensitivity for detecting analytes.
• Poly(dimethylsiloxane) (PDMS) is a versatile polymer with swelling properties sensitive to VOCs.

Purpose of the Study:

• To investigate and demonstrate the functionality of PDMS-based interferometric fiber sensors for VOC detection.
• To compare the performance of Fabry-Perot (FP) and Sagnac interferometer (SI) configurations for VOC sensing.
• To develop a method for differentiating VOCs in gas mixtures using these sensors.

Main Methods:

• Fabrication of FP and SI fiber sensors functionalized with a thin PDMS layer.
• Exposure of sensors to common VOCs (ethanol, 2-propanol) at varying concentrations.
• Measurement of optical path length modulation (FP) and birefringence modulation (SI) due to PDMS swelling.
• Application of the inverse matrix method for analyzing sensor response and differentiating VOCs in mixtures.

Main Results:

• Both FP and SI sensors demonstrated sensitivity to VOCs through polymer swelling.
• The swelling of PDMS resulted in measurable optical path length and birefringence changes.
• The inverse matrix method successfully differentiated between ethanol and 2-propanol in a gas mixture.
• Experimental validation of PDMS-based interferometric sensors for selective VOC detection.

Conclusions:

• PDMS-based interferometric fiber sensors are effective for detecting and differentiating VOCs.
• FP and SI configurations show promise for sensitive VOC monitoring applications.
• The developed method provides a pathway for analyzing complex VOC mixtures using optical fiber sensing technology.