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排序方式: 共有660条查询结果,搜索用时 15 毫秒
71.
Joe W. Tavacoli Job H. J. Thijssen Andrew B. Schofield Paul S. Clegg 《Advanced functional materials》2011,21(11):2020-2027
Bicontinuous, interfacially jammed emulsion gels (bijels) are a class of soft solid materials in which interpenetrating domains of two immiscible fluids are stabilized by an interfacial colloidal monolayer. Such structures form through the arrest of the spinodal decomposition of an initially single‐phase liquid mixture containing a colloidal suspension. With the use of hexalmethyldisilazane, the wetting character of silica colloids, ranging in size and dye content, can be modified for fabricating a novel bijel system comprising the binary liquid ethanediol–nitromethane. Unlike the preceding water‐lutidine based system, this bijel is stable at room temperature and its fabrication and resultant manipulation are comparatively straightforward. The new system has facilitated three advancements: firstly, we use sub 100 nm silica particles to stabilize the first bijel made from low molecular weight liquids that has domains smaller than ten micrometers. Secondly, our new and robust bijel permits qualitative rheological work which reveals the bijel to be significantly elastic and self healing whilst its domains are able to break, reform and locally rearrange. Thirdly, we encapsulate the ethanediol–nitromethane bijel in Pickering drops to form novel particle‐stabilized bicontinuous multiple emulsions that we christen bijel capsules. These emulsions are stimuli responsive – they liberate their contained materials in response to changes in temperature and solvency, and hence they show potential for controlled release applications. 相似文献
72.
Porous materials are currently of great scientific as well as technological interest. A strategy that is increasingly employed to prepare highly porous and well defined macroporous polymers is emulsion templating, whereby the droplets of a high internal phase emulsion are used to create pores in a solid material by curing or polymerization of the emulsion continuous phase. This Feature Article covers recent work in this area, focusing on: the preparation of such materials from new precursors and via novel approaches; the chemical modification of existing materials; and the application of the resulting porous structures in diverse areas of science and technology. 相似文献
73.
Omniphobic coatings are designed to repel a wide range of liquids without leaving stains on the surface. A practical coating should exhibit stable repellency, show no interference with color or transparency of the underlying substrate and, ideally, be deposited in a simple process on arbitrarily shaped surfaces. We use layer‐by‐layer (LbL) deposition of negatively charged silica nanoparticles and positively charged polyelectrolytes to create nanoscale surface structures that are further surface‐functionalized with fluorinated silanes and infiltrated with fluorinated oil, forming a smooth, highly repellent coating on surfaces of different materials and shapes. We show that four or more LbL cycles introduce sufficient surface roughness to effectively immobilize the lubricant into the nanoporous coating and provide a stable liquid interface that repels water, low‐surface‐tension liquids and complex fluids. The absence of hierarchical structures and the small size of the silica nanoparticles enables complete transparency of the coating, with light transmittance exceeding that of normal glass. The coating is mechanically robust, maintains its repellency after exposure to continuous flow for several days and prevents adsorption of streptavidin as a model protein. The LbL process is conceptually simple, of low cost, environmentally benign, scalable, automatable and therefore may present an efficient synthetic route to non‐fouling materials. 相似文献
74.
Heavy direct coal liquefaction products are known to exhibit rapidly increasing viscosities upon prolonged exposure to oxygen. Small-angle X-ray scattering has been used to monitor changes in the colloidal structure of a coal liquid subjected to accelerated aging under an oxygen atmosphere for a total period of 54 days. The data are consistent with an agglomeration model for the formation of large colloidal-size scattering centres which are partially responsible for the rapidly increasing viscosity of the coal liquid. 相似文献
75.
I. Pavel S. Cota W. Kiefer S. Cî nt -Pî nzaru 《Particulate Science and Technology》2006,24(3):301-309
5-Fluorouracil, an extensively used anticarcinogenic drug, was found to undergo a soft adsorption (i.e., no significant structural changes) on the metal surface of different Ag island films (35, 11, 8.7, and 6.5 nm thick). The 35 nm thick film provided the best SERS signal. The resistance of the Ag-complexed species to washing demonstrates the films' advantage over colloids and makes them very attractive for potential bio-applications.
Both deprotonated forms, which were previously detected on colloidal nanoparticles (50 nm diameter) at neutral pH, are also present in this case. However, the interaction mechanism of 5-FU species appears to be substrate dependent. While on colloidal nanoparticles they are orientated perpendicular or significantly tilted from the surface normal, on the much larger Ag-clusters of the island films (20-200 nm) they lie flat, attached through the carbonyl groups and the π-electrons. The charge-transfer mechanism significantly contributes to the rich information SERS reports for this system. 相似文献
Both deprotonated forms, which were previously detected on colloidal nanoparticles (50 nm diameter) at neutral pH, are also present in this case. However, the interaction mechanism of 5-FU species appears to be substrate dependent. While on colloidal nanoparticles they are orientated perpendicular or significantly tilted from the surface normal, on the much larger Ag-clusters of the island films (20-200 nm) they lie flat, attached through the carbonyl groups and the π-electrons. The charge-transfer mechanism significantly contributes to the rich information SERS reports for this system. 相似文献
76.
Pellegrino T Kudera S Liedl T Muñoz Javier A Manna L Parak WJ 《Small (Weinheim an der Bergstrasse, Germany)》2005,1(1):48-63
In this Review, we describe the synthesis of high-quality colloidal nanoparticles in organic solvents, the mechanisms by which they can be transferred into aqueous solution, and some of their applications in biology. In particular, we will place emphasis on the creation of multifunctional nanoparticles or nanoparticle assemblies. 相似文献
77.
Raul P. Moraes Ticiane S. Valera Nicole R. Demarquette Pedro C. Oliveira Maria Lúcia C.P. da Silva Amilton M. Santos 《应用聚合物科学杂志》2009,112(4):1949-1958
The influence of granulometry and organic treatment of a Brazilian montmorillonite (MMT) clay on the synthesis and properties of poly(styrene‐co‐n‐butyl acrylate)/layered silicate nanocomposites was studied. Hybrid latexes of poly(styrene‐co‐butyl acrylate)/MMT were synthesized via miniemulsion polymerization using either sodium or organically modified MMT. Five clay granulometries ranging from clay particles smaller than 75 μm to colloidal size were selected. The size of the clay particles was evaluated by specific surface area measurements (BET). Cetyl trimethyl ammonium chloride was used as an organic modifier to enhance the clay compatibility with the monomer phase before polymerization and to improve the clay distribution and dispersion within the polymeric matrix after polymerization. The sodium and organically modified natural clays as well as the composites were characterized by X‐ray diffraction analysis. The latexes were characterized by dynamic light scattering. The mechanical, thermal, and rheological properties of the composites obtained were characterized by dynamical‐mechanical analysis, thermogravimetry, and small amplitude oscillatory shear tests, respectively. The results showed that smaller the size of the organically modified MMT, the higher the degree of exfoliation of nanoplatelets. Hybrid latexes in presence of Na‐MMT resulted in materials with intercalated structures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
78.
Herein we report on metallization of Cu on to surface‐modified polyimide resin, the method of which relies on potassium hydroxide‐induced modification of the polyimide surface to introduce carboxylic acid groups and incorporation of gold colloids as a seed layer through reduction of chloroauric acid. The contact angle of modified polyimide surface with water changed from 70 to 35° due to the hydrolysis of polyimide. Secondary amine group on the surface was detected with attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectrophotometry, suggesting that tertiary amine group has turned into secondary group. In addition, on the basis of hydrophilic behavior, we succeeded in depositing gold colloids on the chemically modified surface. SEM image of copper electroless plated on polyimide surface indicated that copper particles were compact and about ~ 300 nm in diameter. It showed that gold colloids provide an excellent conductive layer to catalyze the electroless plating of Cu on polyimide surface. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
79.
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