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The sol–gel process is a wet-chemical technique used for the fabrication of both glassy and ceramic materials. In this process, the sol (or solution) evolves gradually towards the formation of a gel-like network containing both a liquid phase and a solid phase.
The first step of the sol-gel process is the creation of a colloidal suspension of solid particles known as a "sol". The precursors are a liquid alcohol such as ethanol which is mixed with a silicon alkoxide , such as tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), and polyethoxydisiloxane (PEDS) (earlier work used sodium silicates). [ 23 ]
The use of nanoparticles and nanofibers to produce specialized nanofabrics became a subject of interest after the sol-gel [12] and electrospinning [13] techniques were fully developed in the 1980s. [14] Since 2000, dramatic increases in global funding have accelerated research efforts in nanotechnology, including nanofabrics research. [15]
[9] [11] [12] It is the second most advertised nanomaterial in consumer products, behind silver nanoparticles. [13] Due to its long use as a commodity chemical, TiO 2 can be considered a "legacy nanomaterial." [14] [15] Ultrafine TiO 2 is used in sunscreens due to its ability to block ultraviolet radiation while remaining transparent on the ...
The size of the particle can be controlled by varying the concentration of silyl ether and alcohol or the micro emulsion method. Mesoporous silica nanoparticles are synthesized by the sol-gel process. They have pores that range in diameter from 2 nm to 50 nm.
A process related to the sol-gel route is the Pechini, or liquid mix, process (named after its American inventor, Maggio Pechini). An aqueous solution of suitable oxides or salts is mixed with an alpha hydroxycarboxylic acid such as citric acid. Chelation, or the formation of complex ring-shaped compounds around the metal cations, takes place ...
The Stöber process is a sol-gel approach to preparing monodisperse (uniform) spherical silica (SiO 2 ) materials that was developed by a team led by Werner Stöber and reported in 1968. [ 1 ] The process, an evolution and extension of research described in Gerhard Kolbe's 1956 PhD dissertation, [ 24 ] was an innovative discovery that still has ...
Mechanics of gelation describes processes relevant to sol-gel process. In a static sense, the fundamental difference between a liquid and a solid is that the solid has elastic resistance against a shearing stress while a liquid does not. Thus, a simple liquid will not typically support a transverse acoustic phonon, or shear wave. Gels have been ...