Prepare Functional Polymers Through Single-Electron Transfer Living Radical Polymerization

Causing overcoming aggregation-induced quenching(ACQ)of raditional fluorescent materials,Aggregation-induced luminescence(AIE)receives extensive attention of the scientific community.The introduction of aggregation-induced emission(AIE)molecules into polymers results in functional materials with AIE characteristics,expanding their scope of applications.In this paper,four tetraphenylethylene bromopropionate initiators with different numbers of initiation sites including:TPE1 Br/TPE-2Br/TPE-3Br/TPE-4Br processing Cu(0)-mediated single Electron transfer living radical polymerization(SET-LRP)were synthesized.SET-LRP kinetics of methyl acrylate(MA)and tert-butyl acrylate(tBA)initiated by four initiators were studied,analyzing chain end functionality.The fluorescence properties of AIE polymers PMA/PtBA with different topologies in solution were studied.The main results are as follows:1.Processing the SET-LRP of MA in DMSO and tBA in DMF initiated with TPE-nBr(n=1-4)and catalyzed by the 12.5 cm nonactivated Cu(0)wire at 25?,polymerization retains first-order kinetics,while kpapp increases with the increasing of the initiation site.kpapp of MA initiated with TPE-1Br,TPE-2Br,TPE-3Br and TPE-4Br appears 0.084,0.091,0.096 and 0.101 min-1,kpapp of tBA initiated with TPE-1Br,TPE-2Br,TPE-3Br and TPE-4Br appears 0.046,0.055,0.061 and 0.071 min-1.Approximatting with Mn,th,Mn,GPC increases linely with the increasing of conversion.And 1H NMR indicated that chain end functionality of the prepared polymers with different topological structures reaches 95%.2.AIE behavior of line polymer including TPE-1Br-PMA emitting at 460 nm and TPE-2Br-PMA emitting at 455 nm in THF/H2O(v/v 5/95)was investigated in THF/water mixtures.While AEE behavior of star polymer including TPE-3Br-PMA emitting at 446 nm and TPE-4Br-PMA emitting at 439 nm in THF/H2O(v/v 5/95)was investigated in THF/water mixtures.Increasing of arm length causes an increase emission intensity in same arm number,and increasing of arm number causes a blue shift in same degree of polymerization.TPE-nBr-PAAxx(n=1-4,xx=50,222)emitting at 470 nm presents strongest PL intensity in B-R buffer solution of pH(1.90).As the pH increases above pKa(4.3),the fluorescence of the polymer aqueous solution gradually weakens until it disappears.The fluorescence behavior of the polymer TPE-PAA appears excellent pH responsiveness.