Dip-coating
Encyclopedia
Dip coating is a popular way of creating thin film
s for research
purposes. Uniform films can be applied onto flat or cylindrical substrates. For industrial process
es, spin coating
is used more often.
In the continuous process, the steps are carried out directly after each other.
Thin film
A thin film is a layer of material ranging from fractions of a nanometer to several micrometers in thickness. Electronic semiconductor devices and optical coatings are the main applications benefiting from thin film construction....
s for research
Research
Research can be defined as the scientific search for knowledge, or as any systematic investigation, to establish novel facts, solve new or existing problems, prove new ideas, or develop new theories, usually using a scientific method...
purposes. Uniform films can be applied onto flat or cylindrical substrates. For industrial process
Industrial process
Industrial processes are procedures involving chemical or mechanical steps to aid in the manufacture of an item or items, usually carried out on a very large scale. Industrial processes are the key components of heavy industry....
es, spin coating
Spin coating
Spin coating is a procedure used to apply uniform thin films to flat substrates. In short, an excess amount of a solution is placed on the substrate, which is then rotated at high speed in order to spread the fluid by centrifugal force...
is used more often.
Process
The dip coating process can be separated into five stages:- Immersion: The substrate is immersed in the solutionSolutionIn chemistry, a solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is dissolved in another substance, known as a solvent. The solvent does the dissolving.- Types of solutions :...
of the coating material at a constant speed (preferably jitter-free). - Start-up: The substrate has remained inside the solution for a while and is starting to be pulled up.
- Deposition: The thin layer deposits itself on the substrate while it is pulled up. The withdrawing is carried out at a constant speed to avoid any jitters. The speed determines the thickness of the coating (faster withdrawal gives thicker coating material).
- Drainage: Excess liquid will drain from the surface.
- Evaporation: The solvent evaporatesEvaporationEvaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....
from the liquid, forming the thin layer. For volatileVolatility (chemistry)In chemistry and physics, volatility is the tendency of a substance to vaporize. Volatility is directly related to a substance's vapor pressure. At a given temperature, a substance with higher vapor pressure vaporizes more readily than a substance with a lower vapor pressure.The term is primarily...
solventSolventA solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
s, such as alcoholAlcoholIn chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
s, evaporation starts already during the deposition & drainage steps.
In the continuous process, the steps are carried out directly after each other.