Sol (colloid)

A sol is a <a href="/facts/Colloid/9EVucqND">colloidal</a> suspension made out of tiny <a href="/facts/Solid/hj5UsXno">solid</a> particles in a continuous <a href="/facts/Liquid/t9GkLWzt">liquid</a> medium. Sols are stable, so that they do not settle down when left undisturbed, and exhibit the <a href="/facts/Tyndall_effect/QJ9I8yeI">Tyndall effect</a>, which is the scattering of light by the particles in the colloid. The size of the particles can vary from 1 nm - 100 nm. Examples include amongst others <a href="/facts/Blood/03zEulkj">blood</a>, <a href="/facts/Pigment/I3clCYkF">pigmented</a> <a href="/facts/Ink/Y7Wj0YQS">ink</a>, cell fluids, <a href="/facts/Paint/Q176AsIG">paint</a>, <a href="/facts/Antacid/CP9PeyQ8">antacids</a> and <a href="/facts/Mud/0zvotxXd">mud</a>.
Artificial sols can be prepared by two main methods: dispersion and condensation. In the dispersion method, solid particles are reduced to colloidal dimensions through techniques such as <a href="/facts/Ball_mill/40Xn4KUQ">ball milling</a> and <a href="/facts/Bredig%27s_arc_method/mKM3BxoP">Bredig's arc method</a>. In the condensation method, small particles are formed from larger molecules through a chemical reaction.
The stability of sols can be maintained through the use of <a href="/facts/Dispersing_agents/EFI5dmry">dispersing agents</a>, which prevent the particles from clumping together or settling out of the suspension. Sols are often used in the <a href="/facts/Sol-gel_process/u4vtn2uj">sol-gel process</a>, in which a sol is converted into a gel through the addition of a <a href="/facts/Crosslinking_agent/zeQ9hEAA">crosslinking agent</a>.
In a sol, solid particles are dispersed in a liquid continuous phase, while in an <a href="/facts/Emulsion/YMSqSCuH">emulsion</a>, liquid droplets are dispersed in a liquid or semi-solid continuous phase.

Sol (colloid) open-in-new

Sol (colloid)