| The main work of this paper was the use of α-bromoisobutyryl bromide and polyethylene glycol(MPEG) to prepare the base bromine macromolecular initiator by esterification reaction, introduced monomer methacryloxyethyl sulfobetaine(SBMA) to the polymerization system, through atom transfer radical polymerization(ATRP), we can obtaine amphiphilic block copolymers including AB-type diblock copolymer MPEGm-b-PSBMAn, as it was a macromolecular initiator trigger monomer 2-(dimethylamino)ethyl methacrylate(DMAEMA) to obtain ABC-type three block copolymer MPEGm-b-PSBMAn-b-PDMAEMAk, the formation of copolymers were confirmed by 1H NMR and GPC. Analysis results showed that this series of block copolymer structure clearly possessed well-defined structure and narrow molecular weight distribution. And the environmental responsive behavior of double block and three block polymers were studied under different chain length, it contained the thermo-sensitive of MPEGm-b-PSBMAn and the thermo-sensitive, pH responsive and CO2/N2 response behavior of MPEGm-b-PSBMAn-b-PDMAEMAk, and resistanting to nonspecific protein adsorption experiment of MPEGm-b-PSBMAn-b-PDMAEMAk was carried out. The main contents include the following three parts:(1) α-bromoisobutyryl bromide was chosen as a small molecule to initiate methoxy polyethylene glycol, and prepared with bromine macromolecular initiator MPEGm-Br by esterification reaction. Macromolecular initiator and monomer SBMA were added into the catalytic system of CuBr/2,2-pyridine, methanol and water as mixed solvent via atom transfer radical polymerization. The AB-type amphiphilic block copolymer of MPEGm-b-SMBAn was obtained. The structure of the polymer was characterized by 1H NMR spectroscopy and permeation gel chromatography.Different molecular weight of block copolymer dissolved in water to prepare the polymer solution with different concentration, using ultraviolet visible spectrophotometer(UV-Vis) to observe the transmittance changes, along with the increasing of temperature the polymer solution was gradually clear, the transmittance of the polymer solution decreased with the increasing of polymer molecular weight and solution concentration under the same temperature condition.The results of UV-Vis showed that the double block polymer had the temperature sensitivity.(2) MPEGm-b-PSBMAn-Br was chosen as macromolecular initiator, the monomer DMAEMA with macromolecular initiator were added into the catalytic system of CuBr/Me6 TREN, water and N, N-dimethyl formamide(DMF) via atom transfer radical polymerization. The ABC-type three block copolymer of MPEGm-b-SMBAn-b-PDMAEMAk was obtained. The structure of the polymer was characterized by 1H NMR spectroscopy and permeation gel chromatography.The block copolymer dissolved in the buffer solution to prepare the polymer solution with different pH, using ultraviolet visible spectrophotometer to observe the transmittance changes, the results showed that under the pH of 4.0 and 6.8, along with the increasing of temperature polymer solution was gradually clear, under the pH of 9.2, the transmittance of the polymer solution first increased then decreased, the solution had a maximum transmittance.Different chain length of three block polymer was dissolved in the buffer solution under the pH of 9.2 to prepare polymer solution with same concentration, saturated CO2 is bubbled into polymer solution, prepared contrast samples to detect transmittance and particle size, and then had the CO2/N2 response to polymer solution experiments, the transmittance changes and particle size changes were detected by ultraviolet visible spectrophotometer and dynamic light scattering(DLS).The results of UV-Vis showed that the polymer had the temperature sensitivity, pH responsive and a certain resilience. The results of DLS showed that the polymer particle size decreased with CO2, the polymer particle size had a minimum without CO2, it was consistent with the results of transmittance changes.(3) MPEGm-b-PSBMAn-b-PDMAEMAk was functionalized with 3-propyl chloride ethoxy silane, coated on the glass surface to make it has the function of resistanting to nonspecific protein adsorption, shocked in bovine serum albumin medium and prepared the comparing experiment, the absorbance of residual broth was detected by ultraviolet visible spectrophotometer which can obtaine the adsorption on the surface of polymer material, the function surface morphology was observed by scanning electron microscopy.Through the absorbance and microscopy showed that the polymer had the performance of resisting to nonspecific protein adsorption. |
PDF Full Text Request