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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 ...
Schematic representation of the different stages and routes of the sol–gel technology. In this chemical procedure, a "sol" (a colloidal solution) is formed that then gradually evolves towards the formation of a gel-like diphasic system containing both a liquid phase and solid phase whose morphologies range from discrete particles to continuous polymer networks.
Gelation can occur either by physical linking or by chemical crosslinking. While the physical gels involve physical bonds, chemical gelation involves covalent bonds. The first quantitative theories of chemical gelation were formulated in the 1940s by Flory and Stockmayer. Critical percolation theory was successfully applied to gelation in 1970s.
Typically, gels are synthesized via sol-gel processing, a wet-chemical technique involving a colloidal solution (sol) that acts as the precursor for an integrated network (gel). There are two possible mechanisms whereby organogels form depending on the physical intermolecular inter-actions, namely the fluid-filled fiber and the solid fiber ...
Random graph theory of gelation is a mathematical theory for sol–gel processes.The theory is a collection of results that generalise the Flory–Stockmayer theory, and allow identification of the gel point, gel fraction, size distribution of polymers, molar mass distribution and other characteristics for a set of many polymerising monomers carrying arbitrary numbers and types of reactive ...
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 ...
Introductory Statistical Mechanics. Oxford University Press. ISBN 978-0-19-850576-1. {}: CS1 maint: multiple names: authors list [80] S. R. De Groot, P. Mazur (2011) Non-Equilibrium Thermodynamics, Dover Books on Physics, ISBN 978-0486647418. Van Vliet, Carolyne M. (2008). Equilibrium and Non-equilibrium Statistical Mechanics. World Scientific ...
A sol is a colloidal suspension made out of tiny solid particles [1] in a continuous liquid medium. Sols are stable, so that they do not settle down when left undisturbed, and exhibit the Tyndall effect, which is the scattering of light by the particles in the colloid. The size of the particles can vary from 1 nm - 100 nm.