Preparation And Properties Of Amphiphilic Aggregation-induced Luminescence Polymer Nanoparticles

In this paper,A series of novel amphiphilic aggregation-induced luminescence polymer nanoparticles were constructed by synthesizing D-A type fluorescent monomer with aggregation-induced luminescence properties and preparing amphiphilic fluorescent block copolymer through RAFT polymerization,and the fluorescence properties of polymer materials were studied.The aggregation induced luminescence properties of polymers were studied in detail.The nanoparticles formed by self-assembly of polymers wrapped the hydrophobic fluorescence groups and enhanced the fluorescence properties of the materials.The relationship between the chemical structure and topological structure of polymer and self-assembled morphology and fluorescence properties was revealed,which provided experimental and theoretical basis for expanding the practical application of fluorescent materials.The main research contents of this paper are as follows:(1)The strong electron acceptor 1,8-naphthalenediimide(NAI)with rigid planar structure is combined with different electron donor units carbazole(CZ),3,6-dimethoxycarbazole(MCZ),3,6-ditert-butylcarbazole(TCZ)and phenothiazine(PTZ),respectively.Four different luminescent D-A aggregation-induced delay fluoromers MANAI-CZ,MANAI-MCZ,MANAI-TCZ and MANAI-PTZ were constructed.The fluorescence emission wavelength can be adjusted by regulating the intensity of the electron donor.When the electron acceptor remains unchanged,the maximum fluorescence emission wavelength of the compound will be redshifted by increasing the intensity of the electron donor,and the corresponding wavelength of the maximum emission peak of solid fluorescence is 531nm,609nm,551nm and 579nm,respectively.The fluorescence emission spectra of the four monomers in dichloromethane(good solvent)and n-hexane(bad solvent)were studied.The fluorescence emission intensity of the four monomers in dichloromethane(good solvent)and n-hexane(bad solvent)was 6.7,220,17 and167 times that of the pure dichloromethane solution when the f_wwas 95%,respectively,indicating that they all had aggregation induced luminescence properties.Transient PL attenuation spectra of man AI-CZ and Man AI-MCZ were tested in aerobic and anaerobic environments.The lifetimes of Man AI-TCZ and Man AI-PTZ in aerobic and anaerobic environments were 10.26ns and 1.2us,10.26ns and 1.6us,with delayed emission.These results indicated that Man AI-TCZ and Man AI-PTZ were novel substances with aggregation-induced delayed fluorescence properties.(2)AIE polymers PMANAI-CZ,PMANAI-MCZ,PMANAI-TCZ and PMANAI-PTZ were prepared by free radical polymerization of the four monomers with aggregation-induced luminescence properties synthesized in Chapter.The corresponding wavelength of the maximum emission peak of polymer solid fluorescence is 531nm,621nm,546nm and 579nm,respectively.Compared with the maximum emission peak of monomer solid,there is almost no shift change.The fluorescence emission spectra of four polymers in dichloromethane(good solvent)and n-hexane(bad solvent)were studied.The fluorescence emission intensity of polymers at 95%f_wwas 1.7times,5.5times,2.5times and 18.4times that of pure dichloromethane solution,respectively,indicating that all polymers have aggregation-induced luminescence properties.(3)MANAI-PTZ,a monomer with aggregation-induced delayed fluorescence,was selected as the hydrophobic segment of amphiphilic block copolymer.Five kinds of AB amphiphilic aggregation-induced delayed fluorescent block copolymers POEGMA-MANAI-PPTZ with different proportions were obtained by reversible addition-breaking chain transfer polymerization(RAFT)of OEGMA monomer with hydrophilic segment.The fluorescence emission spectra of five polymers in dichloromethane(good solvent)and n-hexane(bad solvent)were studied.The fluorescence emission intensity at 95%f_wwas 495 times,672 times,450 times,410times and705 times of pure dichloromethane solution,respectively,indicating that all polymers had aggregation-induced luminescence properties.Five kinds of polymer nanoparticles were prepared by solvent-induced method.The fluorescence enhancement effect of self-assembled polymer nanoparticles was obvious.The particle sizes of the five micellar nanoparticles were197.06nm,202.96nm,223.61nm,234.61nm and 266.36nm,respectively,and their PDI was less than 0.08.With the increase of hydrophobic segments,the size of the core and the size of micelle nanoparticles increased.