One-pot synthesis of fluorescent non-conjugated polymer dots for Fe3+ detection and temperature sensing

Yecang Tang; Xin Zhou; Keke Xu; Xuemei Dong

doi:10.1016/j.saa.2020.118626

One-pot synthesis of fluorescent non-conjugated polymer dots for Fe³⁺ detection and temperature sensing

Spectrochim Acta A Mol Biomol Spectrosc. 2020 Oct 15:240:118626. doi: 10.1016/j.saa.2020.118626. Epub 2020 Jun 19.

Authors

Yecang Tang¹, Xin Zhou², Keke Xu², Xuemei Dong²

Affiliations

¹ College of Chemistry and Materials Science, Anhui Normal University, The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Laboratory of Molecule-Based Materials, Wuhu 241000, China. Electronic address: tycang@mail.ahnu.edu.cn.
² College of Chemistry and Materials Science, Anhui Normal University, The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Laboratory of Molecule-Based Materials, Wuhu 241000, China.

PMID: 32604052
DOI: 10.1016/j.saa.2020.118626

Abstract

The facile preparation of highly fluorescent polymer dots (PDs) still attracts substantial interest. Here, temperature/Fe³⁺ dual-responsive PDs are synthesized under mild conditions via the amidation reaction and self-assembly between hyperbranched polyethyleneimine and 5-aminosalicylic acid. The prepared PDs display strong green fluorescence with quantum yield of 15.5% and 53.3% in water and dimethylsulfoxide, respectively. The PDs also possess unique features, including excellent solubility, solvent polarity-dependent emission, remarkable photostability, as well as good salt-tolerance. Interestingly, the fluorescence intensity of PDs exhibits a reversible and sensitive response to temperature within 20-65 °C, which renders the PDs useful as a thermometer probe. Importantly, Fe³⁺ ion has the specific coordination ability toward the surface groups of PDs, leading to the aggregation and fluorescence quenching of PDs. Thus, the PDs are employed as a fluorescence probe for sensitive detecting Fe³⁺. The fluorescent intensity linearly decreases with increasing Fe³⁺ from 2 to 60 μM. Besides, Fe³⁺ concentration in river water samples is successfully assayed with this developed probe. The non-conjugated PDs with facile preparation, sensitive response to temperature and Fe³⁺ may hold potential applications in environmental monitoring.

Keywords: Fluorescence probe; Iron ions; Polyethyleneimine; Polymer dots; Temperature responsive.