Fe ³⁺ ‐Induced Fluorescence Quenching in Non‐Conjugated Hyperbranched Polysiloxane

ABSTRACT

As a novel polymer material with aggregation‐induced emission (AIE) characteristics, hyperbranched polysiloxane (HBPSi) has garnered significant attention for nuclear magnetic resonance imaging, fluorescent materials and biosensor applications. In this work, two HBPSi derivatives with epoxy and CC terminal groups were fabricated via one‐step transesterification, followed by systematic structural characterization and Fe ³⁺ fluorescence quenching research. Titration data within the measurable concentration gradient demonstrate that the fluorescence signals of both HBPSi samples can be fully suppressed to baseline intensity at 1 × 10 ⁻²  M Fe ³⁺ , with quenching efficiency approaching 100% at this ion concentration. This remarkable quenching capacity illustrates strong ferric ion response performance. Compared with previously reported non‐conjugated polysiloxane fluorescent probes that demand higher metal ion concentrations to achieve complete fluorescence attenuation, the two HBPSi polymers developed herein display favorable aqueous Fe ³⁺ responsiveness. This distinct quenching behavior proves HBPSi can act as a responsive fluorescent probe for aqueous ferric ion detection. The structure‐performance correlation and underlying quenching mechanism are thoroughly discussed to provide guidance for designing advanced polymer sensing materials for environmental and biomedical detection.