Fast and Reversibly Humidity-Responsive Fluorescence Based on AIEgen Proton Transfer

Area of Science:

• Materials Science
• Chemistry

Background:

• Humidity-responsive fluorescent materials are crucial for applications like information encryption and sensors.
• Existing materials suffer from slow response rates and lack specificity.

Purpose of the Study:

• To design and assemble a humidity-responsive fluorescence system with rapid, reversible, and specific moisture response.
• To overcome limitations of current humidity-sensing materials.

Main Methods:

• Developed a system using tetra-(4-pyridylphenyl)ethylene (TPE-4Py) with aggregation-induced emission (AIE) and poly(acrylic acid) (PAA).
• Investigated proton transfer mechanisms between TPE-4Py and PAA in response to varying relative humidity (RH).

Main Results:

• Achieved rapid and reversible changes in fluorescence color and intensity with increasing RH due to TPE-4Py protonation/deprotonation.
• Demonstrated a high response/recovery speed, distinct color changes, and excellent specificity for moisture detection.
• Confirmed reversible and chemically stable proton transfer between TPE-4Py and PAA.

Conclusions:

• The developed humidity-responsive fluorescence system exhibits superior performance characteristics.
• The system's rapid, specific, and reversible response enables diverse applications in transient fluorescent patterning and information encryption.