Dip-coating

For some products, such as early methods of making candles, the process is repeated many times, allowing a series of thin films to bulk up to a relatively thick final object.

The dip coating technique can give uniform, high quality films even on bulky, complex shapes.

The sol-gel technique creates films of increased, precisely controlled thickness that are mainly determined by the deposition speed and solution viscosity.

[4] In another study, porous cellulose nanocrystals and poly(vinyl alcohol) CNC/PVA nanocomposite films with a thickness of 25−70 nm were deposited on glass substrates using dip coating.

This technique starts with the hydrolysis of a liquid precursor (sol), which undergoes poly-condensation to gradually obtain a gel.

A schematic of the continuous dip coating process.
  1. Roll of coarse cloth
  2. Cloth
  3. Bath
  4. Liquid material
  5. Rollers
  6. Oven
  7. Scrapers
  8. Excess liquid falls back
  9. A coating remains on the fabric cloth.