Construction Of Circularly Polarized Luminescent Materials By Helical Substituted Polyacetylenes With AIE Performance

Recently,circularly polarized luminescence materials have received much attention in the fields of 3D naked-eye display,optical data encryption and storage and optical devices.The preparation of circularly polarized luminescence materials with high luminescence dissymmetry factor in solid state is a popular research direction.However,for common luminogens,their fluorescence property generally becomes worse in aggregate and solid states due to the concentration quenching or aggregation-caused quenching effect,thus leading to unsatisfying CPL performance in these cases.The discovery of the phenomenon of aggregation-induced luminescence(AIE)provides a new idea for solving the above problems.Since the discovery of the phenomenon of AIE,researchers have discovered a variety of typical molecules with AIE properties.According to the molecular luminescence mechanism,they can be roughly divided into two categories.Among them,molecules with aromatic ring chromophores and conjugated structures based on molecular motion selectivity(RIM)mechanism draw more interests.Tetraphenylethylene(TPE),as a typical representative of such fluorescent molecules,has the advantages of simple synthesis,easy to modify,and good optical properties.It is often introduced into the desired structure as an AIE-gens.Substituted polyacetylene is a kind of typical dynamic helical polymers,we introduce TPE as AIE-gens into the polyacetylene side group to obtain helical polymers with AIE properties in this thesis.The homopolymers and copolymers with TPE side groups were synthesized separately,and their circularly polarized luminescence properties were studied.The main contents are as follows:Firstly,we synthesized the acetylene monomer M1 bearing TPE pendant for the first time.FT-IR,1H NMR and 13C NMR test results all indicate the successful synthesis of the monomer.This monomer has typical AIE properties in THF/H2O system.We obtained polymers in the form of gel through solution polymerization,which can not dissolve in common solvents even heated.Through research on the formation mechanism of the gel,we found that the gel is formed under the combined action of hydrogen bonding force,?-? stacking and side group steric hindrance.We prepared composite films by filtration of the gel on the surface of nylon-6,and the films combined with monomer films can be used to prepare a simple mono-alcohol recognition fluorescence sensor by using the property of the fluorescence intensity of the films varing with the degree of swelling of the gel;Meanwhile,the composite films can be used as a fluorescence sensors for specifically recognizing trace toluene in water due to the good affinity of the film for toluene.The recognition concentration can reach to 1?L/L,which has great potential application value in the field of water resources protection and monitoring.We also prepared chiral gel by helix-sense-selective polymerization,observed the micro-structure of the gel by SEM,and confirmed the successful chiral transfer between the solution and the gel by the CD spectra.However,the gels with both chirality and fluorescence do not possess CPL properties.Secondly,in order to make the polymer have circularly polarized luminescence,copolymers R-copolymer and S-copolymer were synthesis by copolymerization of the monomer M2 with chiral side groups and the monomer M1 with TPE side groups in ratio of n(M1)/n(M2)=3/7.The copolymer structure was characterized by FT-IR,GPC and other measurement.The enantiomeric copolymer shows typical AIE characteristics in the THF/H2O dispersion system,and has strong chirality.Unfortunately,the copolymer does not have CPL signal due to violation of the "matching rules";Polymers is often prepared into film to obtain more excellent performance,so we put the pair of enantiomeric copolymers into a PMMA composite films.The composite films have extremely strong fluorescence and CD signals.They show a strong circularly polarized luminescence signal due to their meeting the "matching rule",their luminescence asymmetry factor glum can reach up to±3.6×10-2.The "matching rule" can guide the design of materials with high luminescence dissymmetry factor.