Design,Synthesis And Application Of Perylene/Naphthimide Contained Stimuli-responsive Fluorescent Polymers

In recent years,stimuli-responsive fluorescent polymer materials have attracted much attention due to their excellent application value in biological imaging,chemical sensing and super-resolution imaging with their high fluorescence brightness,good solubility,photostability and thermal stability,and easy dispersion in water.Therefore,this thesis mainly divided into two parts: in the first part,based on high quantum yields of perylene imide,two kinds of photoswitchable fluorescent polymer nanoparticles were designed and synthesized.They have excellent photoswitching fluorescence properties,which provided a new way for biological imaging,security and data storage application.In the second part,based on the naphthalimide with good photo-,thermal and chemical stability,a novel polymer fluorescent material that can be responsed by solvent stimulation was prepared,which provided a better method for the application of solvent detection.The main contents and results of this paper are as follows:1.Perylene imide-contained polycaprolactone(TPDI-PCL)and diarylethene-contained polycaprolactone(DTE-PCL)were firstly synthesized via ring-opening polymerization.Based on FRET principle,TPDI-PCL and DTE-PCL were used to construct photoswitchable fluorescent polymer nanoparticles through coprecipitation.By regulating FRET efficiency with a reasonable proportion design,the nanoparticles can achieve a good photoswitching fluorescence effect,which can be successfully applied to photo-rewritable fluorescent pattern.In addition,the nanoparticles also have good water-dispersibility,rapid photo response and excellent photoswitching reversibility,as well as the good biocompatibility and biodegradability brought by the polycaprolactone matrix,which can be directly used as novel nano-probes for reversible phtoswitchable fluorescence imaging in living zebrafish.2.We designed and synthesized a perylene imide-based near infrared fluorescent dye as APr-PDI and photochromic molecule Spirothiopyran derivatives as STPMA.Based on FRET principle,APr-PDI(donor)and STPMA(acceptor)were used to fabricate photoswitchable near infrared fluorescent polymer nanoparticles through miniemulsion polymerization.By regulating FRET efficiency with reasonable proportion design,the nanoparticles can achieve good photoswitching fluorescence effect.In addition,the nanoparticles also dispalyed good water dispersion,rapid photo-response,and excellent photoswitching reversibility,which can be acted as a new fluorescent probe for biological imaging in complex systems.3.Naphthalimide-contained polycaprolactone(NDI-PCL)was prepared via ring-opening polymerization.The flexible polycaprolactone chain at both end groups of NDI-PCL effectively enhanced the solubility of NDI-PCL and inhibited the π-π stacking of NDI nucleus due to ACQ effect,resulting in stronger fluorescence of NDI-PCL.In addition,NDI-PCL showed a large Stokes shift(122nm)between both polar and non-polar solvents,and the emission spectra of NDI-PCL showed a red shift and different colors of fluorescence with the polarity of aromatic solvents decreasing(toluene > xylene > mesitylene).Titration experiments showed that NDI-PCL can detect methanol,toluene or in p-xylene with detection limits of 0.0019% and 0.0002%,and the response speed is very fast(5s).Based on the above excellent fluorescence properties,NDI-PCL is of great significance in the detection of aromatic solvents.