The Environmental Sensitivity Of Phosphorylcholine-based Aba Type Block Copolymer Synthesis And Micelles,

Double hydrophilic block copolymers (DHBCs) were composed of two or more blocks with different chemical properties. Every block of DHBCs should be water-soluble under the appropriate condition. With the changes of external conditions such as temperature, pH or ionic strength and so on, one of the blocks of DHBCs will be water-insoluble, while the other block still remains well-solvated, the block copolymers aggregate micelles and the formed micelles have the typical stimuli-responsive. The stimuli-responsive micelles and the nano matericals have widely prospect in biology, medicine, catalyst and separation and so on.The phosphorylcholine (PC) is the hydrophilic unit of the cell membrane, which has zwitterionic and possesses excellent high hydrophilicity. The PC-based copolymers have the biocompatibility bacause of difficulty absorption and depositional protein, platelet, liposomes biology ingredients. They have some important applications in the fields of biomedical, biochemistry and cosmetic.On the basis of the studies above, the biocompatible, pH-responsive ABA triblock copolymers in which the outer A blocks comprise poly(2-(diethylamino)ethyl methacrylate) and the central B block is poly(2-methacryloyloxyethyl phosphorylcholine) (PDEAEMA-b-PMPC-h-PDEAEMA) were synthesized using atom transfer radical polymerization. The biocompatible, thermo-responsive ABA triblock copolymers in which the outer A blocks comprise poly (N, N-diethylacrylamide) and the central B block is poly (2-methacryloyloxyethyl phosphorylcholine) (PDEAEMA-b-PMPC-b-PDEAEMA) were also synthesized using atom transfer radical polymerization. The properties of aqueous solutions of triblock copolymers and the micellization behavior of the aqueous solutions of triblock copolymers were studied. This dissertation mainly includes two parts as follows:ABA typical triblock copolymer [A=2-(diethylamino) ethylmethacrylate), DEAEMA; B= 2-methacryloyloxyethyl phosphorylcholine, MPC] (PDEAEMA-b-PMPC-b-PDEAEMA) was synthesized via atom transfer radical polymerization (ATRP) in methanol using CuCl/2,2'-bipyridyl as the catalyst system and diethyl-meso-2,5-dibromoadipate as the initiator. PDEAEMA-b-PMPC-b-PDEAEMA was characterized by FT-IR and 1HNMR. The pH sensitivity of the triblock copolymer aqueous solutions was investigated by transmittance and viscosity measurements. The micellization of the triblock copolymer aqueous solutions was investigated by surface tension measurements, fluorescence probe and transmission electron microscope. The results show that the resultant block copolymer has pH sensitivity, and could be formed "flower" micelle through change the solution pH.ABA typical triblock copolymer [A=N,N-diethylacrylamide), DEAM; B= 2-methacryloyloxyethyl phosphorylcholine, MPC] (PDEAM-b-PMPC-b-PDEAM) was synthesized via atom transfer radical polymerization (ATRP) in methanol using CuC1/2, 2'-bipyridyl as the catalyst system and diethyl-meso-2,5-dibromoadipate as the initiator. PDEAM-b-PMPC-b-PDEAM was characterized by FT-IR and 1HNMR. The temperature sensitivity of the triblock copolymer aqueous solutions was investigated by transmittance and viscosity measurements. The micellization of the triblock copolymer aqueous solutions was investigated by surface tension measurements, fluorescence probe and transmission electron microscope. The results show that the resultant block copolymer has temperature sensitivity, and could be formed "flower" micelle through change the solution temperature.