| 1. |
- Adebahr, Josefina, 1973, et al.
(författare)
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Lithium coordination and mobility in gel electrolytes based on an acrylate polymer with ethylene oxide side chains
- 2003
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 1364-5501 .- 0959-9428. ; 13:4, s. 814-817
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Tidskriftsartikel (refereegranskat)abstract
- Multinuclear NMR has been used to investigate the structure and mobility of a series of polymer gel electrolytes. The co-polymers used as matrixes in the gels have acrylate backbones and side chains of ethylene oxide, where the length of the side chains has been varied, while the ratio of acrylate to ethylene oxide has been kept constant. The electrolyte is a mixture of lithium perchlorate and two solvents, ethylene carbonate and gamma butyrolactone. 13 C spectra of the different gel electrolytes shows that both solvents interact with the salt, and that the strength of the interaction increases with decreasing length of the polymer side chains. It also appears that the lithium ions show no selectivity between the two types of solvent. Furthermore, the lithium chemical shift moves progressively upfield with increasing length of the side chains, showing a gradual change in interaction from lithium-solvent to lithium-(ethylene oxide).
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| 2. |
- Akhtar, Farid, et al.
(författare)
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Hierarchically porous binder-free silicalite-1 discs : a novel support for all-zeolite membranes
- 2011
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Ingår i: Journal of Materials Chemistry. - 0959-9428 .- 1364-5501. ; 21:24, s. 8822-8828
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Tidskriftsartikel (refereegranskat)abstract
- Thermal expansion mismatch between the zeolite film and the support is an important cause for the formation of defects and cracks during the fabrication and use of zeolite membranes. We have studied how silicalite-1 discs with a permeability comparable to commercially available alumina supports can be produced by pulsed current processing (PCP) as a novel substrate for all-zeolite membranes. Hierarchically porous and mechanically strong membrane supports where the surface area and crystallography of the silicalite-1 particles were maintained could be obtained by carefully controlling the thermal treatment during PCP consolidation. In situ X-ray diffraction and dilatometry showed that the coefficient of thermal expansion (CTE) of the silicalite-1 substrate was negative in the temperature range 200-800 degrees C while the commonly used alumina substrate displayed a positive CTE. The critical temperature variation, Delta T, and thicknesses for crack-free supported zeolite films with a negative CTE were estimated using a fracture energy model. Zeolite films with a thickness of 1 mu m can only sustain a relatively modest Delta T of 100 degrees when supported onto alumina substrates while the all-zeolite membranes can support temperature variations above 500 degrees
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| 3. |
- Akhtar, Farid, et al.
(författare)
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Hierarchically porous binder-free silicalite-1 discs : a novel support for all-zeolite membranes
- 2011
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 21:24, s. 8822-8828
-
Tidskriftsartikel (refereegranskat)abstract
- Thermal expansion mismatch between the zeolite film and the support is an important cause for the formation of defects and cracks during the fabrication and use of zeolite membranes. We have studied how silicalite-1 discs with a permeability comparable to commercially available alumina supports can be produced by pulsed current processing (PCP) as a novel substrate for all-zeolite membranes. Hierarchically porous and mechanically strong membrane supports where the surface area and crystallography of the silicalite-1 particles were maintained could be obtained by carefully controlling the thermal treatment during PCP consolidation. In situ X-ray diffraction and dilatometry showed that the coefficient of thermal expansion (CTE) of the silicalite-1 substrate was negative in the temperature range 200-800 degrees C while the commonly used alumina substrate displayed a positive CTE. The critical temperature variation, Delta T, and thicknesses for crack-free supported zeolite films with a negative CTE were estimated using a fracture energy model. Zeolite films with a thickness of 1 mu m can only sustain a relatively modest Delta T of 100 degrees when supported onto alumina substrates while the all-zeolite membranes can support temperature variations above 500 degrees.
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| 4. |
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| 5. |
- Andersson, Nina, et al.
(författare)
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One-Pot Synthesis of Well-Ordered Mesoporous Magnetic Carriers
- 2007
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 17:26, s. 2700-2705
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Tidskriftsartikel (refereegranskat)abstract
- The facile preparation of a mesoporous magnetic carrier technology is demonstrated. The micron-sized spherical mesostructured particles are prepared using a newly-developed, one-step, combined emulsion and solvent evaporation (ESE) method. The surfactant-templated silica matrix display a well-ordered internal pore architecture. Very limited pore blocking, and only to a limited degree disordered- or worm-like structures are observed, induced by the iron oxide nanoparticles added to provide the superparamagnetic properties.The iron oxide content was precisely controlled, and the magnetic properties were well preserved during the process. Finally we demonstrate the applicability of the magnetically separable mesoporous material as an adsorbent for specific dissolved materials from dilute aqueous solutions.
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| 6. |
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| 7. |
- Andersson, N, et al.
(författare)
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Photochromic mesostructured silica pigments dispersed in latex films
- 2005
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Ingår i: Journal of Materials Chemistry. - 0959-9428 .- 1364-5501. ; 15:0149-2136, s. 3507-3513
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Tidskriftsartikel (refereegranskat)abstract
- We have incorporated the photochromic dyes spiropyran and spirooxazine in surfactant templated mesostructured silica particles. Spherical inorganic–organic hybrid pigments with varying dye content were produced by a one-pot synthesis in an aerosol reactor where the internal mesostructure could be controlled. The mesostructured inorganic–organic hybrid pigments provide a mechanically and chemically rigid framework that protects the dyes and facilitate handling. We show that an organic latex binder can be used to prepare transparent photochromic films of varying thickness. Changing the dye loading in the pigments and the pigment content in the films provides a versatile route for tuning the photochromic response. The pigmented films show both fast and direct photochromism, where the decay time for thermal bleaching is very fast in the case of spirooxazine doped pigments (kSO= 0.094 s–1), being in the range of the best reported values for solid state composites.
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| 8. |
- Antoni, Per, et al.
(författare)
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Europium confined cyclen dendrimers with photophysically active triazoles
- 2008
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 18:22, s. 2545-2554
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Tidskriftsartikel (refereegranskat)abstract
- Dendrimers up to the fourth generation (G1-G4) were successfully synthesized via the efficient copper catalyzed 1,3-dipolar cycloaddition between primary alkynes and azides (CuAAC), also referred to as a click reaction. The synthetic protocol involved the preparation of presynthesized dendron wedges that subsequently were attached to a tetra-valent alkyne functional cyclen core. These constructed structures integrated stable triazole groups "intra-locked'' between the cyclen and dendron wedges. The incorporation of a lanthanide metal ion, europium, into the interior of all cyclen dendrimers was monitored by FT-IR. Interestingly, the photophysical results showed that the proximate triazole not only acts as a stable linker but also as a sensitizers, transferring its singlet-singlet excitation in the ultraviolet region (270-290 nm) to the partially filled luminescent lanthanide 4f shell. An increase of luminescence decay time from the lanthanide D-5(0) -> F-7(2) emission was observed with increasing dendrimer size, indicating that the shielding effect of the dendron wedges is important for the relaxation of the photo-excitation and energy transfer. To the best of our knowledge, this is the first time a set of dendron wedges have successfully been attached to a cyclen metal ion cage via the versatile click reaction. Furthermore, the produced triazoles intra-locked in close proximity to the macrocycle core elucidated an interesting photophysical function.
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| 9. |
- Asfaw, Habtom Desta, et al.
(författare)
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Emulsion-templated bicontinuous carbon network electrodes for use in 3D microstructured batteries
- 2013
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Ingår i: Journal of Materials Chemistry. - United Kingdom. - 0959-9428 .- 1364-5501. ; 1:44, s. 13750-13758
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Tidskriftsartikel (refereegranskat)abstract
- High surface area carbon foams were prepared and characterized for use in 3D structured batteries. Twopotential applications exist for these foams: firstly as an anode and secondly as a current collector supportfor electrode materials. The preparation of the carbon foams by pyrolysis of a high internal phase emulsionpolymer (polyHIPE) resulted in structures with cage sizes of 25 mm and a surface area enhancement pergeometric area of approximately 90 times, close to the optimal configuration for a 3D microstructuredbattery support. The structure was probed using XPS, SEM, BET, XRD and Raman techniques; revealingthat the foams were composed of a disordered carbon with a pore size in the <100 nm range resultingin a BET measured surface area of 433 m2 g-1. A reversible capacity exceeding 3.5 mA h cm2 at acurrent density of 0.37 mA cm-2 was achieved. SEM images of the foams after 50 cycles showed thatthe structure suffered no degradation. Furthermore, the foams were tested as a current collector bydepositing a layer of polyaniline cathode over their surface. High footprint area capacities of500 mA h cm-2 were seen in the voltage range 3.8 to 2.5 V vs. Li and a reasonable rate performancewas observed.
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| 10. |
- Babushkin, Oleg, et al.
(författare)
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Thermal expansion of hot isostatically pressed hydroxyapatite
- 1994
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Ingår i: Journal of Materials Chemistry. - 0959-9428 .- 1364-5501. ; 4:3, s. 413-415
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Tidskriftsartikel (refereegranskat)abstract
- A dense and transparent hydroxyapatite produced by hot isostatic pressing was investigated with respect to its stability and thermal expansion behaviour in the range 20–1150 °C. The evaluation was made by high-temperature X-ray diffraction in a reconstructed test chamber with a BN sample holder and Pt as an internal (in situ) reference. No degradation of the hydroxyapatite was detected in the range investigated. The lattice parameters, a and c, were determined as a function of temperature. The linear thermal expansion coefficient, determined by dilatometry, was 17.1 × 10–6°C–1, which agreed well with the value 17.3 × 10–6°C–1 obtained by X-ray diffraction.
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