Study On The Synthesis And Properties Of Sequence-controlled Functionalized Polymers

With the wide study of functional polymers,it is the focus of polymer science to reveal the intermolecular and intramolecular interactions from the relationship of structure and property.Due to the unique sequence structures,the relationships between structure and properties of sequence-controlled functionalized polymers have been widely concerned.However,because of the difficulty in synthesis of sequence polymers,few studies have been reported by now.Base on the previous research of our group,the SiH pendant groups sequence arrangement well-defined functionalized polymers were synthesized via living anionic polymerization,which contain uniform sequence(Uni-),alternative(Alt-and qua-Alt-),gradual(Gra-)and interval(Int-)sequence structure of styrene(St)and 1,1-diphenylethylene(DPE)derivatives.With those backbones,the sequence-controlled side chain liquid crystal polymers(SCLCPs)and fluorescent polymers(FPs)are prepared through an efficient and convenient hydrosilylation,and the relationship between the sequence structure and the liquid crystal performance(LCP)or fluorescent performance were explored:1.The sequence-controlled backbones were adhered by three varying linker designs of cholesteric liquid crystal moieties using highly efficient hydrosilylation to yield SCLCPs.The study compared the effect of sequence backbones and linkers on the LCP.The results of?T and LCP showed Uni-SCLCPs>Alt-/qua-Alt-SCLCPs>Gra-SCLCPs>Int-SCLCPs.SCLCPs bearing long flexible linker showed better LCP.Furthermore,T_i and?T of SCLCPs containing ester linkers were 10-20 ~oC higher than those with ether linkers.2.The sequence-controlled backbones were adhered by two different coumarin fluorescent unites using hydrosilylation to yield FPs.The study compared the effect of well-designed backbones and monomers with similar structure on the fluorescent performance.Comparing the qualitative maximum fluorescence intensity(FL)and the quantitative fluorescence quantum yield(?_F)of monomers and FPs,fluorescent performance demonstrated M_b>M_a,FPs-M_b>FPs-M_a and Alt-/qua-Alt-FPs>Gra-FPs~Uni-FPs>Int-FPs.