Colloidal gold is a suspension (or colloid) of sub-micrometre-sized particles of gold in a fluid — usually water. The liquid is usually either an intense red colour (for particles less than 100 nm), or a dirty yellowish colour (for larger particles). Due to the unique optical, electronic, and molecular-recognition properties of gold nanoparticles, they are the subject of substantial research, with applications in a wide variety of areas, including electron microscopy, electronics, nanotechnology, and materials science.
Properties and applications of colloidal gold nanoparticles strongly depend upon their size and shape. For example, rodlike particles have both transverse and longitudinal absorption peak, and anisotropy of the shape affects their self-assembly.
Read more about Colloidal Gold: History, Synthesis, Electron Microscopy
Famous quotes containing the word gold:
“When you have eaten your fill and have built fine houses and live in them, and when your herds and flocks have multiplied, and your silver and gold is multiplied, and all that you have is multiplied, then do not exalt yourself, forgetting the LORD your God, who brought you out of the land of Egypt, out of the house of slavery...”
—Bible: Hebrew, Deuteronomy 8:12-14.