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排序方式: 共有594条查询结果,搜索用时 31 毫秒
491.
Sugikawa K Numata M Kaneko K Sada K Shinkai S 《Langmuir : the ACS journal of surfaces and colloids》2008,24(23):13270-13275
A great deal of attention has been focused on exploiting novel methods to fabricate thin carbonaceous capsules from multiple components for advanced materials. A layer-by-layer (LbL) method is therefore being introduced to synthesize thin and multi-carbon nanotube (CNT)-based hollow capsules from CNT complexes with cationic or anionic complementarily functionalized beta-1,3-glucans as building-blocks. These ionic beta-1,3-glucans wrap around single-walled carbon nanotubes (SWNTs) and double-walled carbon nanotubes (DWNTs) to form water-soluble complexes with ionic groups on their exterior surface. Alternate self-assembly of these CNT complexes on the silica particles is demonstrated in solution by electrostatic interactions. The LbL adsorption processes were carefully monitored by zeta-potential measurements, frequency shifts of a quartz crystal microbalance (QCM), and electron micrographs. Silica particles were then dissolved away by HF acid to obtain CNT-based hollow capsules composed of SWNTs and DWNTs. We believe that these novel surface adsorption methods are useful for potential design of CNT-based advanced functional materials. 相似文献
492.
Junko Konishi Koji Fujita Kazuki Nakanishi Shotaro Nishitsuji Mikihito Takenaka Kiyotaka Miura Kazuyuki Hirao 《Journal of Sol-Gel Science and Technology》2008,46(1):63-69
Titania (TiO2) monoliths with well-defined bicontinuous macropores and gel skeletons were prepared through the alkoxy-derived sol–gel process
accompanied by spinodal decomposition, and the structural evolution during evaporation drying and heat treatment was probed
by a combination of ultra-small-angle X-ray scattering and small-angle X-ray scattering. X-ray scattering profiles of wet
and dried gels revealed that microporous structures related to the existence of primary particles are present in the gel skeletons
at the wet stage and are preserved during drying. Additionally, it is found that the primary particles swollen in the wet
condition are dried to compact aggregates to produce the smooth surface of gel skeletons. Upon heating at 400 °C, the particle–particle
correlation associated with regularity of mesostructures is enhanced. From nitrogen adsorption–desorption measurements, the
average pore size is less than 1 nm in the dried gel and increases to 3.1 nm by the heat treatment. Homogeneous growth of
primary particles due to interparticle-polycondensation reaction is responsible for the increased size and uniform distribution
of mesopores in the heat-treated gel. 相似文献
493.
We demonstrated the metal-organic framework bearing the azide group in the organic linkers and in situ click reactions with some small alkynes. The XRPD patterns indicated that the click reaction proceeded without any decomposition of the original MOF network. Controlling the organic linkers and incorporation of the azide groups should provide the designer-made MOFs that have controlled molecular cavities with the desired steric dimensions and functionality. 相似文献
494.
Nagashima K Yanagida T Tanaka H Seki S Saeki A Tagawa S Kawai T 《Journal of the American Chemical Society》2008,130(15):5378-5382
Heterostructured transition metal oxide nanowires are potential candidates to incorporate rich functionalities into nanowire-based devices. Although the oxide heterointerface plays a crucial role in determining the physical properties, the effects of the heterointerface on the oxide nanowire's properties have not been clarified. Here we investigate for the first time the significant role of the heterointerface in determining the transport properties of well-defined MgO/titanate heterostructured nanowires by combining a technique for in situ formation of a oxide heterointerface and microwave conductivity measurement. Variation of the heterointerface strongly affects the nanowire's transport properties due to the crystallinity and the atomic interdiffusion at the oxide heterointerface. Thus, the precise in situ formation of a well-defined heterointerface is crucial to create oxide heterostructured nanowires with the desired transport properties. 相似文献
495.
Preparation methods of monolithic silica columns for HPLC including the surface modification were reviewed. Chemical modification methods recently reported to obtain stationary phases for reversed-phase (RP), chiral, ion-exchange, and hydrophilic interaction chromatography (HILIC) separations were discussed. Recent results related to preparation methods of monolithic silica were also covered. The characteristics and properties of silica monoliths and some applications of monolithic silica columns for different analytical and bioanalytical fields will be commented. 相似文献
496.
Stereoblock poly(lactic acid) (sb-PLA) is incorporated into a 1:1 polymer blend system of poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA) that has a high molecular weight to study its addition effect on the stereocomplex (sc) formation of PLLA and PDLA. The ternary polymer blend films are first prepared by casting polymer solutions of sb-PLA, PLLA, and PDLA with different compositions. Upon increasing the content of sb-PLA in the blend films the sc crystallization is driven to a higher degree, while the formation of homo-chiral (hc) crystals is decreased. Lowering the molecular weight of the incorporated sb-PLA effectively increases the sc formation. Consequently, it is revealed that sb-PLA can work as a compatibilizer to improve the poor sc formation in the polymer blend of PLLA and PDLA. 相似文献
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500.
Hideki Sugimoto Go Nishino Naoki Tsuzuki Kazuki Daimatsu Katsuhiro Inomata Eiji Nakanishi 《Colloid and polymer science》2012,290(2):173-181
In this study, high oxygen permeable transparent hybrid copolymers were prepared with hydrophilic monomer such as 2-hydroxyethylmethacrylate
(HEMA) or N,N-dimethylacrylamide (DMAA) and mono- or difunctional silicone macro-monomer introduced methacryl groups. In HEMA-based hybrid copolymers, difunctional silicone macro-monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker were required in order to prepare
transparent hybrid materials, while high transparent DMAA-based hybrid copolymers could be prepared without EGDMA cross-linker.
The polymerization kinetics investigation revealed that this difference between HEMA and DMAA in preparation condition to
transparent hybrid material originated to monomer reactivity in copolymerization and DMAA showed high reactivity compared
with HEMA. Moreover, DMAA-based hybrid copolymers indicated high water content and high oxygen permeability as against HEMA-based
hybrid copolymers because of its low cross-linking density. 相似文献