Polymer Optical Microcavity Sensor for Volatile Organic Compounds with Distinct Selectivity toward Aromatic...

Area of Science:

• Materials Science
• Chemical Sensing
• Optoelectronics

Background:

• Volatile organic compounds (VOCs) pose environmental and health risks.
• Existing sensors often lack selectivity and sensitivity for specific VOCs.
• Whispering-gallery mode (WGM) optical sensors offer potential for high-sensitivity detection.

Purpose of the Study:

• To develop a highly selective and sensitive WGM optical resonance sensor for VOC detection.
• To utilize fluorescent polymer microspheres doped with β-cyano-appended oligo(p-phenylenevinylene) (β-COPV).
• To investigate the sensor's performance with aromatic hydrocarbons.

Main Methods:

• Fabrication of β-COPV-doped polystyrene (PS) microspheres (MS_COPV) via miniemulsion method.
• Utilizing the spectral shift of WGM resonance peaks upon VOC permeation into the PS matrix.
• Evaluating permeation efficiency based on chemical affinity between VOCs and the polymer.

Main Results:

• MS_COPV expand and exhibit spectral shifts when exposed to VOCs.
• The sensor demonstrates exceptional selectivity towards aromatic hydrocarbons like benzene, toluene, and xylenes (BTXs).
• Achieved high sensitivity and selectivity, outperforming conventional surface adsorption-based WGM sensors.

Conclusions:

• The developed MS_COPV sensor offers a promising platform for selective VOC detection.
• The mechanism relies on polymer matrix expansion and spectral shift, not just surface adsorption.
• This technology advances selective chemical sensing for environmental monitoring and diagnostics.