Mean-square bond length, root-mean-square end-to-end distance and gyration radius in diblock copolymer films have been studied by dissipative particle dynamics simulations. Results show evident linear trends of any pr...Mean-square bond length, root-mean-square end-to-end distance and gyration radius in diblock copolymer films have been studied by dissipative particle dynamics simulations. Results show evident linear trends of any property separately with the thickness of film, the interaction between particles of different types, the repulsion between particle and boundary, except for the dependence of the variations of mean-square bond length on the thickness of film, which exhibits as a wave trend. What＇s more, the varying trends of mean-square bond length and root-mean-square end-to-end distance can correspond to each other. The density distribution of either component in diblock copolymer film can be controlled and adjusted effectively through its interaction with boundary.展开更多
The microphase-separating behaviors of two types of star-diblock copolymers （Ax）4（By）4 and （A^Bg）4 in thin films are studied using the simulation technique of dissipative particle dynamics. A variety of ordered ...The microphase-separating behaviors of two types of star-diblock copolymers （Ax）4（By）4 and （A^Bg）4 in thin films are studied using the simulation technique of dissipative particle dynamics. A variety of ordered mesostructures have been observed and the simulated phase diagrams show obvious symmetries for the （Ax）4（By）a films and asymmetries for the （AxBy）4 films, besides, it is easier for the （Ax）4（By）4 than for the （A^By）4 to carry out microphase separation under the same conditions, which has been recognized in bulk and can be ascribed to the structural difference between the two types of star copolymers. There are some correspondences between the mesostructures formed in the film and those formed in bulk at the same composition fraction. Decreasing the thickness of film and strengthening the A-B repulsion both help the mesostructures enhance the degree of order. Composition fraction dependences of the mean-square radius of gyration in the two types of star copolymer films are almost contrary, which can be attributed to the differences in their respective structures. These findings can provide a guide to designing novel microstructures involving star-diblock copolymers via geometrical confinement.展开更多
A new kind of comblike copolymer film composed of acrylic acid-polyethylene glycol monomethyl ether acrylate copolymer（AA-PEGMA copolymer） was successfully synthesized to immobilize hemoglobin（Hb）. FTIR, UV-Vis an...A new kind of comblike copolymer film composed of acrylic acid-polyethylene glycol monomethyl ether acrylate copolymer（AA-PEGMA copolymer） was successfully synthesized to immobilize hemoglobin（Hb）. FTIR, UV-Vis and CD spectra suggest that Hb kept its original structure in the AA-PEGMA copolymer film without denaturation. A pair of well-defined, quasi-reversible cyclic voltammetric peaks at around –270 mV vs. saturated calomel electrode（SCE） for the Hb Fe（III）/Fe（II） redox couple was observed on the film-modified electrode in phos phate buffer solution（PBS, pH=7.0）. The formal potential of Hb/AA-PEGMA copolymer film-modified electrode is linearly dependent on solution pH with a slope of –46.3 mV/pH, illustrating that one-proton transfer was accompa nied with each electron transfer. Furthermore, the modified electrode displayed electrocatalytic response to the reduc tion of H2O2 with a linear range of 3.5―126 μmol/L and a detection limit of 1.17 μmol/L. In conclusion, the AA-PEGMA copolymer film was proved to be an excellent matrix for the immobilization and electrochemistry of proteins.展开更多
Temperature dependence of microscopic properties in diblock copolymer films has been investigated by dissipative particle dynamics simulations. Results show the relation between mean-square bond length （MSBL） and sy...Temperature dependence of microscopic properties in diblock copolymer films has been investigated by dissipative particle dynamics simulations. Results show the relation between mean-square bond length （MSBL） and system temperature can be described as a quadratic curve. The root-mean-square radius of gyration （RMSGR） and end-end distance （RMSED） increase gradually as the temperature rises and composition fraction changes from 0.1 to 0.5, in which the effect of the former is primary. Especially, the relation between RMSGR and temperature is nearly linear in the confinement-introduced direction. Density distribution of each component in the films can be controlled and adjusted effectively by its interaction with other components and boundaries. Moreover, the changes of system temperature and composition fraction can both affect the density distributions to a certain extent.展开更多
Ordered porous block copolymer films（PBCFs） have attracted much attention because of their potential applications in several fields. In this paper, we first reported a non-destructive, controllable, and efficient ap...Ordered porous block copolymer films（PBCFs） have attracted much attention because of their potential applications in several fields. In this paper, we first reported a non-destructive, controllable, and efficient approach for preparation of β-cyclodextrin（β-CD）-functionalized PBCFs（β-CD-PBCFs）. The key point of the approach is to incorporate β-CD units into the hydrophilic segment of amphiphilic block copolymers before the preparation of films. β-CD-PBCFs with structural integrity and controllable pore parameters were fabricated through combining of self-assembly and breath figure methods. And then, the effective adsorption capacity of β-CD-PBCFs toward Congo red was confirmed through UV-Vis spectroscopy and was found to be affected by β-CD content and solution p H values. Adsorption kinetic results showed that the adsorption behavior of β-CD-PBCFs was consistent with the pseudo-second-order kinetic model and the chemisorption mechanism.展开更多
A new kind of amphiphilic copolymer was synthesized with azo bond functional side chains, and elementary studies about formation of I,B film, UV-visible spectra and photoelectrical properties of multilayers of this ki...A new kind of amphiphilic copolymer was synthesized with azo bond functional side chains, and elementary studies about formation of I,B film, UV-visible spectra and photoelectrical properties of multilayers of this kind of amphiphilic copolymer were reported.展开更多
The morphologies of triblock copolymer/homopolymer blend films, ABA/A and ABAIB, confined between two neutral hard walls were studied via Monte Carlo （MC） simulation on a simple .cubic lattice. The effects of φh （...The morphologies of triblock copolymer/homopolymer blend films, ABA/A and ABAIB, confined between two neutral hard walls were studied via Monte Carlo （MC） simulation on a simple .cubic lattice. The effects of φh （the volume fraction of homopolymer） and Md/Mb （the molecular weight of homopolymer in relation to that of the corresponding blocks in the copolymer） on the morphologies were investigated in detail.展开更多
A series of acrylonitrile (AN) copolymers with methyl acrylate (MA) or ethyl acrylate (EA) as comonomer (5-23 wt%) was prepared by free-radical copolymerisation. The permeability coefficients of the copolymers to oxyg...A series of acrylonitrile (AN) copolymers with methyl acrylate (MA) or ethyl acrylate (EA) as comonomer (5-23 wt%) was prepared by free-radical copolymerisation. The permeability coefficients of the copolymers to oxygen and carbon dioxide were measured at 1.0 MPa and at 30 degrees C, and those to water vapor also measured at 100% relative humidity and at 30 degrees C. All the AN/acrylic copolymers are semicrystalline. As the acrylate content increase, the permeability coefficients of the copolymers to oxygen and carbon dioxide are increased progressively, but those to water vapor are decreased progressively. The gas permeability coefficients of the polymers were correlated with free-volume fractions or the ratio of free volume to cohesive energy.展开更多
A series of vinylidene dichloride (VDC) copolymers with methyl acrylate (MA) as comonomer (3-12wt%), was prepared by free-radical suspension copolymerization. The permeability coefficients of the copolymers to oxygen ...A series of vinylidene dichloride (VDC) copolymers with methyl acrylate (MA) as comonomer (3-12wt%), was prepared by free-radical suspension copolymerization. The permeability coefficients of the copolymers to oxygen and carbon dioxide were measured at 1.0 MPa and at 30 degrees C, and those to water vapor were measured at 30 degrees C and 100% relative humidity. All the VDC/MA copolymers studied are semicrystalline. As the MA content increases, the permeability coefficients of the copolymers to oxygen, carbon dioxide, and water vapor are progressively increased, caused by decrease in crystalline fraction and increase in free volume of VDC/MA copolymers.展开更多
文摘Mean-square bond length, root-mean-square end-to-end distance and gyration radius in diblock copolymer films have been studied by dissipative particle dynamics simulations. Results show evident linear trends of any property separately with the thickness of film, the interaction between particles of different types, the repulsion between particle and boundary, except for the dependence of the variations of mean-square bond length on the thickness of film, which exhibits as a wave trend. What＇s more, the varying trends of mean-square bond length and root-mean-square end-to-end distance can correspond to each other. The density distribution of either component in diblock copolymer film can be controlled and adjusted effectively through its interaction with boundary.
文摘The microphase-separating behaviors of two types of star-diblock copolymers （Ax）4（By）4 and （A^Bg）4 in thin films are studied using the simulation technique of dissipative particle dynamics. A variety of ordered mesostructures have been observed and the simulated phase diagrams show obvious symmetries for the （Ax）4（By）a films and asymmetries for the （AxBy）4 films, besides, it is easier for the （Ax）4（By）4 than for the （A^By）4 to carry out microphase separation under the same conditions, which has been recognized in bulk and can be ascribed to the structural difference between the two types of star copolymers. There are some correspondences between the mesostructures formed in the film and those formed in bulk at the same composition fraction. Decreasing the thickness of film and strengthening the A-B repulsion both help the mesostructures enhance the degree of order. Composition fraction dependences of the mean-square radius of gyration in the two types of star copolymer films are almost contrary, which can be attributed to the differences in their respective structures. These findings can provide a guide to designing novel microstructures involving star-diblock copolymers via geometrical confinement.
基金Supported by the National Natural Science Foundation of China(No.21076065)
文摘A new kind of comblike copolymer film composed of acrylic acid-polyethylene glycol monomethyl ether acrylate copolymer（AA-PEGMA copolymer） was successfully synthesized to immobilize hemoglobin（Hb）. FTIR, UV-Vis and CD spectra suggest that Hb kept its original structure in the AA-PEGMA copolymer film without denaturation. A pair of well-defined, quasi-reversible cyclic voltammetric peaks at around –270 mV vs. saturated calomel electrode（SCE） for the Hb Fe（III）/Fe（II） redox couple was observed on the film-modified electrode in phos phate buffer solution（PBS, pH=7.0）. The formal potential of Hb/AA-PEGMA copolymer film-modified electrode is linearly dependent on solution pH with a slope of –46.3 mV/pH, illustrating that one-proton transfer was accompa nied with each electron transfer. Furthermore, the modified electrode displayed electrocatalytic response to the reduc tion of H2O2 with a linear range of 3.5―126 μmol/L and a detection limit of 1.17 μmol/L. In conclusion, the AA-PEGMA copolymer film was proved to be an excellent matrix for the immobilization and electrochemistry of proteins.
基金Project supported by the Shanghai Leading Academic Discipline Project(Grant No.S30109)the Research and Development Special Fundation of Excellent Young Teachers of Universities in Shanghai,the Developmental Foundation of Scientific Technology of Shanghai Universitythe Innovation Foundation of Shanghai University
文摘Temperature dependence of microscopic properties in diblock copolymer films has been investigated by dissipative particle dynamics simulations. Results show the relation between mean-square bond length （MSBL） and system temperature can be described as a quadratic curve. The root-mean-square radius of gyration （RMSGR） and end-end distance （RMSED） increase gradually as the temperature rises and composition fraction changes from 0.1 to 0.5, in which the effect of the former is primary. Especially, the relation between RMSGR and temperature is nearly linear in the confinement-introduced direction. Density distribution of each component in the films can be controlled and adjusted effectively by its interaction with other components and boundaries. Moreover, the changes of system temperature and composition fraction can both affect the density distributions to a certain extent.
基金financially supported by the National Natural Science Foundation of China (Nos. 21374088 and 21674086)the Fundamental Research Funds for the Central Universities (Nos. 3102017jc03006 and 3102017jc01001)
文摘Ordered porous block copolymer films（PBCFs） have attracted much attention because of their potential applications in several fields. In this paper, we first reported a non-destructive, controllable, and efficient approach for preparation of β-cyclodextrin（β-CD）-functionalized PBCFs（β-CD-PBCFs）. The key point of the approach is to incorporate β-CD units into the hydrophilic segment of amphiphilic block copolymers before the preparation of films. β-CD-PBCFs with structural integrity and controllable pore parameters were fabricated through combining of self-assembly and breath figure methods. And then, the effective adsorption capacity of β-CD-PBCFs toward Congo red was confirmed through UV-Vis spectroscopy and was found to be affected by β-CD content and solution p H values. Adsorption kinetic results showed that the adsorption behavior of β-CD-PBCFs was consistent with the pseudo-second-order kinetic model and the chemisorption mechanism.
基金The project is supported by the Key Laboratory of Molecular Spectroscopy and Structure, National Education Commission of China
文摘A new kind of amphiphilic copolymer was synthesized with azo bond functional side chains, and elementary studies about formation of I,B film, UV-visible spectra and photoelectrical properties of multilayers of this kind of amphiphilic copolymer were reported.
基金Acknowledgements This work is supported by the National Natural Science Foundation of China （Projects No. 20236010. 20476025, 20490200）. E-Institute of Shanghai High Institution Grid （No.200303） and Shanghai Municipal Education Commission of China.
文摘The morphologies of triblock copolymer/homopolymer blend films, ABA/A and ABAIB, confined between two neutral hard walls were studied via Monte Carlo （MC） simulation on a simple .cubic lattice. The effects of φh （the volume fraction of homopolymer） and Md/Mb （the molecular weight of homopolymer in relation to that of the corresponding blocks in the copolymer） on the morphologies were investigated in detail.
基金The project is supported by the National Natural Science Foundation of China
文摘A series of acrylonitrile (AN) copolymers with methyl acrylate (MA) or ethyl acrylate (EA) as comonomer (5-23 wt%) was prepared by free-radical copolymerisation. The permeability coefficients of the copolymers to oxygen and carbon dioxide were measured at 1.0 MPa and at 30 degrees C, and those to water vapor also measured at 100% relative humidity and at 30 degrees C. All the AN/acrylic copolymers are semicrystalline. As the acrylate content increase, the permeability coefficients of the copolymers to oxygen and carbon dioxide are increased progressively, but those to water vapor are decreased progressively. The gas permeability coefficients of the polymers were correlated with free-volume fractions or the ratio of free volume to cohesive energy.
基金This project supported by the National Natural Science Foundation of China
文摘A series of vinylidene dichloride (VDC) copolymers with methyl acrylate (MA) as comonomer (3-12wt%), was prepared by free-radical suspension copolymerization. The permeability coefficients of the copolymers to oxygen and carbon dioxide were measured at 1.0 MPa and at 30 degrees C, and those to water vapor were measured at 30 degrees C and 100% relative humidity. All the VDC/MA copolymers studied are semicrystalline. As the MA content increases, the permeability coefficients of the copolymers to oxygen, carbon dioxide, and water vapor are progressively increased, caused by decrease in crystalline fraction and increase in free volume of VDC/MA copolymers.
