Synthesis And Properties Of Fluorescent Oranogels Based On Tetraphenylethylene

Gels are three-dimensional networks filled with dispersed media,and their viscosity,density,pore size,elasticity,and volume can be controlled by controlling temperature,polymer chain or solvent properties,and the properties and number of dissolved solute molecules.In addition,the structure of the gel can change depending on how it is made.In addition to the excellent properties of gels such as biocompatibility and controllable viscoelasticity,countless researchers have continuously optimized the physical and chemical properties of gels,and they have been widely used in new biological materials.With its unique luminescence properties and superior mechanical and physical and chemical properties,fluorescent gels have great potential in environmental sensing,biological imaging and tissue engineering applications,and become a research hotspot of the new generation of gels.Introducing fluorophore into the gel skeleton through covalent bond or noncovalent bond or forming fluorophore through self-assembly is a common way to form fluorophore gel.However,the phenomenon of Aggregation-caused Quenching(ACQ)of traditional fluorescent gels and the complicated preparation process restrict the large-scale development of gels.The theory of aggregation-induced Emission(AIE)provides an effective way to solve the Aggregation quenching problem of traditional fluorescent gels.AIE fluorescence gel prepared by combining aggregation induced fluorophore with gel has brought a breakthrough in the field of biomedicine application.However,the complex synthesis process and the sensitivity of fluorescence regulation are still the difficult problems faced by fluorescent gels.In order to quickly and efficiently synthesize fluorescent gels and better regulate their fluorescence properties,amino tetraphene reacted with hexamethylene diisocyanate to prepare a crosslinking agent with isocyanate group in this paper,and then reacted with polymer backbone molecules.Using organic solvent as gel medium,AIE fluorescent organic gels SATPE-PVA,TATPE-PVA,TATPE-PEG were prepared.And the mechanical properties and fluorescence properties of the gel were explored respectively.The main contents include:1.Tetraminosubstituted tetraphene crosslinking agent(TATPE-CL)and monoaminosubstituted tetraphene crosslinking agent(SATPE-CL)and polyvinyl alcohol(PVA)through the affinity addition reaction between isocyanate group and hydroxyl group,using dimethyl sulfoxide as medium,the gel network is formed under the action of covalent and non-covalent bonds.Therefore,the AIE fluorescence organic gel was prepared,which is sensitive to anion and temperature and has good mechanical strength.The mechanical and fluorescence properties of the prepared gel were characterized by Fourier transform infrared spectroscopy(FT-IR),ultraviolet absorption spectroscopy(UV-Vis),fluorescence emission spectroscopy(FL),scanning electron microscopy(SEM)and texture analyzer.The mechanical properties of SATPE-PVA gel and TATPE-PVA gel were enhanced compared with PVA gel.The fluorescence properties of the gel samples showed that the two prepared gels showed enhanced fluorescence phenomenon with the addition of PO43-and HPO42-,and the fluorescence intensity of the gel gradually increased with the increase of the amount of ions added.On the basis of this experiment,this paper tried to add Adenosine triphosphate(ATP)to the gel,and the results of fluorescence data showed that the gel would also have fluorescence enhancement due to the addition of ATP.These results indicate that SATPE-PVA and TATPE-PVA can be used as potential carriers of phosphate-based drugs to treat diseases.In addition,the fluorescence gel will change with the change of temperature,when the temperature increases from 20℃ to 70℃,the fluorescence intensity decreases gradually.And vice versa.Fluorescence intensity gradually increased,showing fluorescence enhancement.2.The gel network formed by polyvinyl alcohol containing a large number of hydroxyl groups had strong stability,which affects the sensitivity of AIEgens in the gel to ions.In order to make the gel more sensitive to ions and reduce the influence of gel network on fluorescence,this paper changed the polymer skeleton from PVA to polyethylene glycol(PEG)with the same functional group,and prepared the fluorescent organic gel TATPE-PEG.The gel samples were characterized by fluorescence spectrum and ultraviolet absorption spectrum.The gel samples were characterized by fluorescence spectrum and ultraviolet absorption spectrum.The results show that TATPE-PEG has fluorescence response to metal ions,temperature and organic solvents.Of all the metal ions used,the gel is the most responsive to Pd2+.When Pd2+ was added,the gel underwent fluorescence quenching.In this paper,a new complex of Pd2+ and TATPEPEG was confirmed by ultraviolet absorption spectra.It is speculated that the emergence of new complexes affects the fluorescence emission of fluorophores and leads to fluorescence quenching.The gels with different organic solvents as gel medium also show different fluorescence intensities,among which TATPE-PEG methanol gel has the strongest fluorescence intensity,while TATPE-PEG acetone gel has the weakest fluorescence intensity.The fluorescence intensity of TATPE-PEG gel shows different fluorescence intensity at different temperatures.When the temperature rises from 10℃ to 80℃,the fluorescence intensity decreases gradually.Conversely,the intensity of fluorescence increases gradually.