The structure of micelles formed by two poly(oxyethylene)/poly(oxybutylene) block copolymers, E 76B 38 and E 155B 76, in n-hexane at 50 ℃ was studied by synchrotron Small Angle X-ray Scattering(SAXS) and Wide Angle X...The structure of micelles formed by two poly(oxyethylene)/poly(oxybutylene) block copolymers, E 76B 38 and E 155B 76, in n-hexane at 50 ℃ was studied by synchrotron Small Angle X-ray Scattering(SAXS) and Wide Angle X-ray Scattering(WAXS). Spherical micelle with a crystalline core was observed for E 155B 76. E 76B 38 also formed spherical micelles, but the core was amorphous. The radius of the core(R), the length of the amorphous chain in the shell(L) and the number of association(N) were obtained by fitting the SAXS data with the model of a spherical core attached with Gaussian chains. The result showed that the E block exhibited multiple folds. The B block tended to be more coiled and the area occupied by per chain was larger in the micelles of E 155B 76, which are favorable to the formation of spherical micelles.展开更多
In this paper, the self-assembly of PS 43-b-PEO 45-b-PS 43 triblcok copolymer was investigated. The colloids were made by firstly dissolving the copolymer in the common solvents, including THF, 1,4-dioxane, and DMF, t...In this paper, the self-assembly of PS 43-b-PEO 45-b-PS 43 triblcok copolymer was investigated. The colloids were made by firstly dissolving the copolymer in the common solvents, including THF, 1,4-dioxane, and DMF, then droping water into the corresponding copolymer solution to induce the self-assembly. The aggregates prepared were characterized with TEM and AFM techniques. The experimental results demonstrated that the self-assembled vesicles were formed when THF and 1,4-dioxane were used as the common solvents to dissolve the copolymer, comparatively, using DMF as the common solvent resulted in the formation of spherical aggregates. The self-assembled aggregates observed, possessing hierarchical structures, could be used as either the nanostructures themselves for drug delivery systems, separations, catalysts, and so on, or templates or building blocks for more complex structures.展开更多
By means of TEM, SDP, 29Si NMR etc analysis, the behavior of the Polyethylene Oxide (PEO) Polypropylene Oxide (PPO) Polyethylene Oxide (PEO) as organic modifier on SiO2 sol gel in the basic media was investigated; the...By means of TEM, SDP, 29Si NMR etc analysis, the behavior of the Polyethylene Oxide (PEO) Polypropylene Oxide (PPO) Polyethylene Oxide (PEO) as organic modifier on SiO2 sol gel in the basic media was investigated; the effects on sol particle growth and network &morphology control were discussed in detail, and then the model on sol particle growing was suggested on the basis of growth unit theory of anion coordinate polyhedron. The results showed that PEO PPO PEO additive limited particle growth but also restrained particle agglomeration and then made the SiO2 sol high stable. It was found that the action of EPE was similar to that of organic structure directing agent and made the sol cluster cross linked branch network.展开更多
文摘The structure of micelles formed by two poly(oxyethylene)/poly(oxybutylene) block copolymers, E 76B 38 and E 155B 76, in n-hexane at 50 ℃ was studied by synchrotron Small Angle X-ray Scattering(SAXS) and Wide Angle X-ray Scattering(WAXS). Spherical micelle with a crystalline core was observed for E 155B 76. E 76B 38 also formed spherical micelles, but the core was amorphous. The radius of the core(R), the length of the amorphous chain in the shell(L) and the number of association(N) were obtained by fitting the SAXS data with the model of a spherical core attached with Gaussian chains. The result showed that the E block exhibited multiple folds. The B block tended to be more coiled and the area occupied by per chain was larger in the micelles of E 155B 76, which are favorable to the formation of spherical micelles.
文摘In this paper, the self-assembly of PS 43-b-PEO 45-b-PS 43 triblcok copolymer was investigated. The colloids were made by firstly dissolving the copolymer in the common solvents, including THF, 1,4-dioxane, and DMF, then droping water into the corresponding copolymer solution to induce the self-assembly. The aggregates prepared were characterized with TEM and AFM techniques. The experimental results demonstrated that the self-assembled vesicles were formed when THF and 1,4-dioxane were used as the common solvents to dissolve the copolymer, comparatively, using DMF as the common solvent resulted in the formation of spherical aggregates. The self-assembled aggregates observed, possessing hierarchical structures, could be used as either the nanostructures themselves for drug delivery systems, separations, catalysts, and so on, or templates or building blocks for more complex structures.
文摘By means of TEM, SDP, 29Si NMR etc analysis, the behavior of the Polyethylene Oxide (PEO) Polypropylene Oxide (PPO) Polyethylene Oxide (PEO) as organic modifier on SiO2 sol gel in the basic media was investigated; the effects on sol particle growth and network &morphology control were discussed in detail, and then the model on sol particle growing was suggested on the basis of growth unit theory of anion coordinate polyhedron. The results showed that PEO PPO PEO additive limited particle growth but also restrained particle agglomeration and then made the SiO2 sol high stable. It was found that the action of EPE was similar to that of organic structure directing agent and made the sol cluster cross linked branch network.
