Fluorescent hyperbranched polysiloxane (HBPSi) has attracted increasing attention due to its good biocompatibility. However, its emission mechanism remains an open question. Unfortunately, the excitation spectra of HBPSi are rarely systematically investigated and show a narrow excitation band, which hinders the emission mechanism study. Herein, we synthesized a series of novel HBPSi containing L-glutamic acid (HBPSi-GA). Surprisingly, these polymers have four excitation peaks and two emission peaks, which are caused by the energy transfer from free functional groups to heterogeneous electron delocalizations in different clusters. Meanwhile, the fluorescence and biocompatibility of HBPSi-GA are significantly improved with increasing L-glutamic acid. Furthermore, HBPSi-GA exhibits dual stimuli-responsive fluorescence to temperature and Fe 3+ as well as potential application in cell imaging. This research possesses important guidance to develop multiexcitation unconventional fluorescent polymers.

This review constructed a framework of methodologies to summarize the recent progress of high-performance conductive hydrogels for flexible electronics and further provide novel insights about rational design of the advanced hydrogels.

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