Study On The Stimulus Response And Fluorescence Properties Of Nitrogen-containing Hyperbranched Polymers

Stimuli-responsive polymer materials have attracted scientists?s attention.Combining the stimulus response and luminescence properties of polymers makes them easier to use in a variety of biological applications.In this work,we synthesized two nitrogen-containing multistimuli-responsive polymers,azobenzene derivatives and photoluminescent polyethyleneimine and studied their temperature sensitivity and fluorescence properties.Details are as follows:In the first part,a hyperbranched polyamide-amine(HPA-Azo)containing azo functional groups was designed and synthesized.It was found that its aqueous solution could respond to the stimulation of ultraviolet light,carbon dioxide and pH,and the structure of the polymer changed accordingly.This transformation could reversibly adjust the size,structure and temperature sensitivity of the polymer,so that the cloud point temperature of the polymer could switch reversibly between different temperatures.The cloud point temperature of the polymer varies with the concentration under different hydrophobic and hydrophobic ratios.In the second part,hyperbranched polyethyleneimide(IP-HPEI)with photoluminescence properties was prepared by heating viscous high purity polyethylene solids in air.Hydrogen nuclear magnetic resonance(H-NMR),Fourier transform infrared spectroscopy(FTIR),X-ray energy spectroscopy(XPS)and fluorescence characterization showed that air oxidation resulted in the formation of luminogen in HPEIs.At the same time,IP-HPEI was modified by isobutyrylation.The derivatives obtained not only have thermosensitive properties,but also have reversible response to various gases.Finally,the application of IP-HPEI in ion detection is discussed.The prepared IP-HPEI can selectively detect Cu²⁺ions.