Micro silica nanoparticles

Fluorescent silica nanoparticles, called FloDots, were created by Yao et al. (2006) by two synthetic routes. Hydrophilic particles were produced using a reverse micro-emulsion process, wherein detergent micelles formed in a water-in-oil system form discrete nanodroplets in which the silica particles are formed. The addition of water-soluble fluorescent dyes resulted in the entrapment of dye molecules in the silica nanoparticle. In an alternative method, dye molecules were entrapped in silica using the Stober process, which typically results in hydrophobic particles. Either process resulted in luminescent particles that then can be surface modified with... 

Abstract We review various methods for the photochemical grafting of organic polymers to various substrates including, organic films, membranes, planar gold, silicon wafers, glass, silica gel, silica nanoparticles, and polydimethylsiloxane micro-channels. An emphasis is placed on photoinitiated synthesis of polymer brushes from planar gold and silicon. 

Silica particles synthesized in nonionic w/o microemulsions (e.g., poly-oxythylene alkyl phenyl ether/alkane/water) typically have a narrow size distribution with the average value between 25 and 75 nm [54,55]. Both water and surfactant are necessary components for the formation of stable silica suspensions in microemulsions. The amounts of each phase present in the micro emulsion system has an influence on the resulting size of the silica nanoparticle. The role of residual water (that is the water that is present in the interface between the silica particle and the surfactant) is considered important in providing stability to the silica nanoparticle in the oil... 

Dense Silica Coatings on Micro- and Nanoparticles by Deposition of Monosilicic Acid... 

These silica nanoparticles generate surface roughness on the polybenzoxazine nanocomposite film, possessing both micro- and nanoscale binary structures. In addition, its appropriate chemical structure allows for reversible wettability operation. The as-prepared superhydrophobic surface is not wettable by pure water. Mohammad et al. [13] reported that aqueous solutions of various surfactants were able to wet a superhydrophobic surface since these surfactants reduced the siuface tension of the solutions. Soeno and co-workers [14] also reported wetting of their superhydrophobic surfaces with a water/ethanol mixture. In this study, ethanol was chosen to reduce the surface tension of the solvent and shift the superhydrophobic polymer film into wettable film through a relatively milder condition. 

The mechanical properties of PA-based polymers can also be enhanced through the incorporation of inorganic micro- and nanofillers such as silica nanoparticles. Thus, the maximum value of stress at yield point (72 MPa) was observed in hybrid materials containing 10 wt% silica and the maximum stress at break point increased up to 66 MPa in PA-sUica hybrids containing 20 wt% silica (compared with 44 MPa for the silica-free PA system). Also, the tensile modulus was found to increase up to 2.59 GPa upon incorporation of 10 wt% silica within the polymeric matrix [268]. 

C. Kaiser, M. Hanson, H. Giesche, J. Kinkel, and K.K. Unger Nonporous Silica Microsheres in the Micron and Submicron Range Manufacture, Characterization and Application, in Fine Particle Science and Technology From Micro to Nanoparticles, NATO AST Series (E. Pelizetti, ed) KlUwer Academic Publishers, Dordrecht, NL (1996) 71-84... 

Figure 5.19 TEM image of nano-spheres prepared by (a) micro-emulsion or (c) sol-gel techniques, (b) Two-photon scanning microscopy of MDA-MB-231 cancer cells stained with anti-CFR conjugated nanoparticle, (d) Two-photon luminescence images of single silica nanoparticles. Adapted with permission from [124]. Copyright 2010, John Wiley and [125] Copyright 2008, Royal Society of Chemistry...

However, it has to be realized that biological templates remain inserted in the final nanoparticles and this is not acceptable for many applications. Nevertheless, some recent examples indicate that such biomimetic materials may be suitable for the design of biotechnological and medical devices [32]. For instance, it was shown that silica gels formed in the presence of p-R5 were excellent host matrices for enzyme encapsulation [33]. In parallel, biopolymer/silica hybrid macro-, micro- and nanocapsules were recently obtained via biomimetic routes and these exhibit promising properties for the design of drug delivery materials (see Section 3.1.1) [34,35],... 

The strategy of this method is to utilize the inherent porosity of bulky substrates in the construction of hierarchical stractures by incorporating additional pore systems. Diatoms are unicellular algae whose walls are composed of silica with an internal pore diameter at submicron to micron scales. Zeolitization of diatoms, in which zeolite nanoparticles are dispersed on the surface of diatoms followed by a hydrothermal conversation of a portion of the diatom silicas into zeolites, resulted in the formation of a micro/mesoporous composite material. Similarly, wood has also been used as a substrate to prepare meso/macroporous composites and meso/macroporous zeolites. After the synthesis, wood is removed by calcination. ... 

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