Highly solvent-dependent naphthalene diimide-based fluorescent polymer sensors for detecting p-xylene

Abstract

P-xylene (PX), as one of xylenes, is a kind of very important chemical raw material. It is generally fabricated using methanol (MeOH) and toluene (TOL), and serves as a useful intermediary. However, it is difficult to use a simple and convenient tool to distinguish it from TOL and MeOH. Herein, we reported a simple naphthalene diimide-based polycaprolactone polymer (NDI-PCL) as a high-sensitive fluorescent sensor for xylene detection from MeOH and TOL. NDI-PCL was synthesized via ring-opening polymerization (ROP) of ε-caprolactone. NDI-PCL showed a remarkable fluorescence change from blue to green and yellow because of the formation of charge transfer (CT) interaction between naphthalene diimide (NDI) and aromatic solvents. NDI-PCL was successfully applied as the high-sensitive sensor for discriminating binary solvent mixtures such as PX in TOL, MeOH in PX, and MeOH in TOL, and their limit of detection (LOD) were as low as 19 ppm, 16 ppm and 9 ppm. These excellent fluorescence properties ensured that NDI-PCL indicated great potential application in detecting aromatic solvents.

Graphical Abstract

Keywords:

• p-xylene
• fluorescent sensor
• polymer
• naphthalene diimide
• charge transfer

Acknowledgments

We gratefully acknowledge the financial support by NSFC (52273206, 52273290), Hunan Provincial Natural Science Foundation of China (2021JJ10029), and Huxiang High-level Talent Gathering Project (2022RC4039).

Disclosure statement

There are no conflicts of interest to declare.

Additional information

Funding

National Natural Science Foundation of China.