pH-responsive fluorescence chemical sensor constituted by conjugated polymers containing pyridine rings

Area of Science:

• Materials Science
• Polymer Chemistry
• Chemical Sensing

Background:

• Conjugated polymers offer unique optical properties for sensing applications.
• Developing efficient and reusable chemical sensors for environmental monitoring is crucial.
• Poly(p-pyridinium phenylene ethynylene)s (PPyPE) are promising candidates due to their tunable electronic structures.

Purpose of the Study:

• To synthesize novel PPyPEs with alternating donor-acceptor units.
• To investigate the pH-responsive fluorescence behavior of these PPyPEs.
• To evaluate their potential as chemical sensors for pH detection.

Main Methods:

• Sonogashira coupling reaction for PPyPE synthesis.
• Characterization using FT-IR, NMR, UV-visible, and fluorescence spectroscopy.
• Protonation/deprotonation studies in solution with acid/base titration.

Main Results:

• Successful synthesis of PPyPEs with pyridine units.
• Demonstrated pH-dependent changes in fluorescence intensity and spectral shifts.
• Observed reversible fluorescence quenching and enhancement with pH variation.

Conclusions:

• The synthesized PPyPEs function as effective and reusable pH-responsive fluorescence chemical sensors.
• The pyridine units in the polymer backbone are key to the pH-sensing mechanism.
• These materials show potential for real-time monitoring of pH changes.