Supramolecular Hyperbranched Poly(amino ester)s with Homogeneous Electron Delocalization for Multi‐Stimuli‐Responsive Fluorescence

• Published in: Macromolecular materials and engineering Vol. 305; no. 6
• Main Authors: Bai, Lihua, Yan, Hongxia, Wang, Lianlian, Bai, Tian, Yuan, Luyao, Zhao, Yan, Feng, Weixu
• Format: Journal Article
• Language: English
• Published: Weinheim John Wiley & Sons, Inc 01.06.2020
• Subjects: Assemblies; Chromophores; DFT calculation; Emission; Fluorescence; Hydrogen bonds; hyperbranched poly(amino ester)s; multi‐stimuli responsivity; Polycondensation reactions; self‐assembly; Stimuli
• ISSN: 1438-7492; 1439-2054
• DOI: 10.1002/mame.202000126

Nonconventional luminogens without conjugated chromophores have attracted much interest for their intriguing fluorescence and potential wide applications. Their emission mechanism, however, remains an open question. Herein, hyperbranched poly(amino ester) (HPAE) with novel structure is synthesized through a simple one‐pot polycondensation reaction. The HPAE exhibits strong fluorescence and aggregation‐induced emission (AIE) characteristic. Transmission electron microscopy and theoretical calculation results demonstrate that the fluorescence is attributed from electron delocalization in the supramolecular self‐assemblies of HPAE. Meanwhile, supramolecular self‐assemblies, induced by the synergy effect of inter/intramolecular hydrogen bond and amphipathicity of HPAE, rigidify the molecule conformation, leading to enhanced fluorescence. Furthermore, the HPAE exhibits single‐color emission due to its generation of homogeneous electron delocalization. Interestingly, such HPAE shows multi‐stimuli‐responsive fluorescence to solvent, temperature, pH, and Fe3+. Therefore, this work not only provides an important step forward in exploring the emission mechanism of nonconventional luminogens, but also develops a multi‐functional unconjugated AIE probe. A novel single‐color emission hyperbranched poly(amino ester) is synthesized through simple one‐pot polycondensation of malic acid and triethanolamine (without any catalyst). Notably, the synthesized hyperbranched poly(amino ester) exhibits aggregation‐induced emission properties, and the electron delocalization acts as the emission center. More interestingly, such hyperbranched poly(amino ester) shows multi‐stimuli‐responsive fluorescence to solvent, temperature, pH, and Fe3+ ions.