Study On The Synthesis And Micellar Behavior Of PPEGMEMA-b-PPy

In this thesis,poly[poly(ethylene glycol)methyl ether methacrylate](PPEGMEMA)and its block copolymer poly[poly(ethylene glycol)methyl ether methacrylate]-b-poly[(1-pyrene)methylmethacrylate](PPEGMEMA-b-PPy)were synthesized by the radical polymerization in the presence of 1,1 Diphenylethene(DPE),using 2,2'-azoisobutyronitrile(AIBN)as initiator.Then,the amphiphilic block copolymer,PPEGMEMA-b-PPy was assembled into micelles in water by solvent diffusion methods.The structure and micellar behavior of the block polymer were characterized and tested.Firstly,PPEGMEMA was synthesized by the radical polymerization in the presence of DPE,with AIBN as initiator and toluene as solvent.The effects of reaction time,temperature,DPE and initiator concentration on the polymerization were investigated.The structure of PPEGMEMA was characterized by FT-IR,1H-NMR and GPC.The lower critical solution temperature of PPEGMEMA was The results showed that the PPEGMEMA with DPE segment was synthesized;the conversion of PEGMEMA increased with polymerization time increased,and the kinietic curves of PEGMEMA polymerization revealed good linear relationships;the molecular weight of PPEGMEMA was increased along with monomer conversion,and the molecular weight distribution was narrow;when the ratio of[DPE]to[AIBN]increased,the polymerization rate and molecular weight of PPEGMEMA were decreased and the molecular weight distribution becomes narrower.The water-soluble PPEGMEMA exhibited a lower critical solution temperature(LCST).Secondly,the 1-pyrenylmethyl methacrylate(Py)was synthesized by the reaction of 1-pyrenylmethanol and methacryloyl chloride,then the amphiphilic block copolymer PPEGMEMA-b-PPy was synthesized by DPE method,using PPEGMEMA as macromolecular precursors and Py as monomer.The structure of PPEGMEMA-b-PPy was characterized by FT-IR,1H-NMR and Gel Permeation Chromatography(GPC).The results showed that the molecular weight of PPEGMEMA-b-PPy increased with Py conversion increased,the kinetic curves of the polymerization revealed good linear relationship,and the molecular weight distribution was less than two.Thirdly,the micelle of amphiohilic block copolymer PPEGMEMA-b-PPy was prepared by solvent diffusion methods,using THF as solvent.The size,morphology and photoresponsiveness of the micelles were determined by transmission electron micrograph(TEM),fluorescene spectrometer,dynamic light scattering(DLS)and UV-vis.The results showed that micelle assembled into spherical aggregates;when the increasing the irradiation time of UV light,the partical size and fluorescene intensity decreased,the transmmitance increased and the micellar solution became clear;the mecelles have good photoresponsiveness.