| 1. |
- Fan, Chaxing, et al.
(författare)
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Formation of chiral mesopores in conducting polymers by chiral lipid ribbon templating and “seeding” route
- 2008
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Ingår i: Advanced Functional Materials. - : Wiley. - 1616-301X .- 1616-3028. ; 18:18, s. 2699-2707
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Tidskriftsartikel (refereegranskat)abstract
- Conducting polymer nanofibers with controllable chiral mesopores in the size, the shape, and handedness have been synthesized by chiral lipid ribbon templating and “seeding” route. Chiral mesoporous conducting poly(pyrrole) (CMPP) synthesized with very small amount of chiral amphiphilic molecules (usually < 3%) has helically twisted channels with well-defined controllable pore size of 5–20 nm in central axis of the twisted fibers. The structure and chirality of helical mesopores have been characterized by high-resolution transmission electron microscope (HRTEM), scanning electron microscope (SEM) and electron tomography. The average pore diameters of chiral mesopores were approximately estimated from the N2 adsorption–desorption data and calculated by the conversion calculation from helical ribbons to a rectangular straight tape. The pore size of CMPP has been controlled by choosing different alkyl chain lengths of chiral lipid molecules or precisely adjusting the H2O/EtOH volume ratio.
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| 2. |
- Gao, Chuanbo, 1981-, et al.
(författare)
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Formation of Diverse Mesophases Templated by a Diprotic Anionic Surfactant
- 2008
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Ingår i: Chemistry - A European Journal. - Weinheim : Wiley-VCH Verlag GmbH&Co. KGaA. - 0947-6539 .- 1521-3765. ; 14:36, s. 11423-11428
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis system for mesophase formation, using the diprotic anionic surfactant N-myristoyl-l-glutamic acid (C14GluA) as the structuredirecting agent (SDA) and N-trimethoxylsilylpropyl-N,N,N-trimethylammonium chloride (TMAPS) as the co-structure-directing agent (CSDA), has been investigated and a full-scaled synthesis-field diagram is presented. In this system we have obtained mesophases including three-dimensional (3D) micellar cubic Fm-3m, Pm-3n, Fd-3m, micellar tetragonal P42/mnm, two-dimensional (2D) hexagonal p6mm and bicontinuous cubic Pn-3m, by varying the C14GluA/NaOH/TMAPS composition ratios. From the diagram it can be concluded that the mesophase formation is affected to a high degree by the organic/inorganicinterface curvature and the mesocage–mesocage electrostatic interaction. Bicontinuous cubic and 2D-hexagonalphases were found in the low organic/inorganic-interface curvature zones, whereas micellar cubic and tetragonal mesophases were found in the high organic/inorganic-interface curvature zones. Formation of cubic Fm-3m and tetragonal P42/mnm was favoured in highly alkaline zones with strong mesocage–mesocage interactions, and formation of cubic Pm-3n and Fd-3m was favoured with moderate mesocage–mesocage interactions in the less alkaline zones of the diagram.
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| 4. |
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| 5. |
- Han, Lu, et al.
(författare)
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Carboxylic group functionalized ordered mesoporous silicas
- 2011
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 21:30, s. 11033-11039
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Tidskriftsartikel (refereegranskat)abstract
- Many research efforts have focused on the synthesis of organic and inorganic hybrid ordered mesoporous silicas (MSs) with functionalization of the exterior and/or interior surfaces aiming for applications in separation, adsorption, catalysis, drug delivery, and nanotechnology. Among the organic groups, the carboxylic group is a particularly useful reactive group for many applications. This article provides a brief overview of the carboxylic group functionalized MSs and the recent progress in synthetic strategies and applications have been reviewed.
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| 6. |
- Han, Lu, et al.
(författare)
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Crystal twinning of bicontinuous cubic structures
- 2020
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Ingår i: IUCrJ. - 2052-2525. ; 7, s. 228-237
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Tidskriftsartikel (refereegranskat)abstract
- Bicontinuous cubic structures in soft matter consist of two intertwining labyrinths separated by a partitioning layer. Combining experiments, numerical modelling and techniques in differential geometry, we investigate twinning defects in bicontinuous cubic structures. We first demonstrate that a twin boundary is most likely to occur at a plane that cuts the partitioning layer almost perpendicularly, so that the perturbation caused by twinning remains minimal. This principle can be used as a criterion to identify potential twin boundaries, as demonstrated through detailed investigations of mesoporous silica crystals characterized by diamond and gyroid surfaces. We then discuss that a twin boundary can result from a stacking fault in the arrangement of inter-lamellar attachments at an early stage of structure formation. It is further shown that enhanced curvature fluctuations near the twin boundary would cost energy because of geometrical frustration, which would be eased by a crystal distortion that is experimentally observed.
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| 7. |
- Han, Lu, et al.
(författare)
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Evolution of Packing Parameters in the Structural Changes of Silica Mesoporous Crystals : Cage-Type, 2D Cylindrical, Bicontinuous Diamond and Gyroid, and Lamellar
- 2011
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 133, s. 11524-11533
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Tidskriftsartikel (refereegranskat)abstract
- Cage-type, two-dimensional (2D) cylindrical hexagonal (C), bicontinuous diamond (D), bicontinuous gyroid (G), and one-dimensional (1D) lamellar (L) structures of silica mesoporous crystals (SMCs) were obtained by using the anionic surfactant N-stearoyl-L-glutamic acid (C(18)GluA) as a template in the presence of the nonionic surfactant C(16)(EO)(10) (Brij-56). The mesostructures were controlled by the organic/inorganic interface curvature change induced by Brij-56. A synthesis-field diagram showed that the mesostructure changed in the sequence cage-type -> C -> intergrowth of C and D -> intergrowth of C and G -> D -> G -> L with increase of the amount of Brij-56. Mixed micelles were formed by the anionic and nonionic surfactants, the packing parameter g of which increased with increasing the addition amount of nonionic surfactant and the reaction temperature. The local g parameter was obtained from electron crystallography reconstruction results by calculating mean curvatures and Gaussian curvatures from the equi-electrostatic potential surface. The intergrowth of C and D and two kinds of intergrowth of C and G are also discussed.
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| 8. |
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| 9. |
- Han, Lu, et al.
(författare)
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Silica-Based Nanoporous Materials
- 2014
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Ingår i: Zeitschrift für Anorganische und Allgemeines Chemie. - : Wiley. - 0044-2313 .- 1521-3749. ; 640:3-4, s. 521-536
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Forskningsöversikt (refereegranskat)abstract
- Ordered nanoporous structures are among the most fascinating and industrially important materials currently in use. The archetypal zeolite material has now been joined by an eclectic array of new structures that exhibit porosity over a wide range of length scales and with order/disorder expressed in a multitude of ways. This raises the bar in terms of characterization and extends a real challenge to the scientific community to fully understand the properties and potential future applications of such materials. In this review we discuss the importance of modern microscopy tools combined with diffraction in this endeavour and show how the details of even the most complex quasi-crystalline nanoporous architectures can be elucidated. We show by using the appropriate spherical aberration (C-s) corrections in scanning transmission electron microscopy it is possible to decipher all the individual silicon and aluminum atoms in a zeolite structure. Automated routines for using large electron diffraction datasets for crystal structure determination of nanocrystals is described making the need for large single crystal synthesis less-and-less important. The power of complementary combinations of surface tools such as atomic force microscopy and high-resolution scanning electron microscopy is discussed to elucidate crystal growth mechanisms. For mesoporous materials synthesized from self-organized organic mesophases electron microscopy reveals the details of the complex hierarchy of porosity so crucial for the functional performance of the structure.
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| 10. |
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