Spray-Printed UiO-66/Polyaniline Composite Films: Tuning MOF Content and Conductivity for Enhanced Ammonia Detection

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Low-concentration ammonia detection is crucial for environmental, agricultural, and occupational safety.
• Existing sensors often lack sufficient sensitivity, selectivity, or stability.

Purpose of the Study:

• To develop and optimize a metal-organic framework (MOF)/conducting polymer nanocomposite for enhanced chemiresistive ammonia sensing.
• To investigate the impact of MOF loading and deposition techniques on sensor performance.

Main Methods:

• In situ polymerization to synthesize UiO-66/polyaniline (PANI) nanocomposites.
• Contactless spray-deposition technique for fabricating uniform sensor films.
• Systematic optimization of UiO-66 loading for gas-sensing applications.

Main Results:

• The optimized 5 wt % UiO-66/PANI sensor achieved 138% sensitivity at 100 ppb ammonia, a ~3x improvement over pristine PANI.
• Demonstrated excellent selectivity, stability under humidity variations, and long-term cyclic performance.
• Open-space demonstration confirmed real-time monitoring capability comparable to commercial sensors.

Conclusions:

• UiO-66/PANI nanocomposites offer a practical platform for sensitive and selective ammonia detection.
• The developed spray-deposition method ensures device reproducibility and film uniformity.
• This work presents a systematic approach for optimizing MOF/polymer composites for gas sensing.