What is supercritical drying?

6 This process of drying affects the total surface tension of the substance, causing fine structures to break or degenerate. To avoid this problem, there is a supercritical drying that dries the substance with high heat and pressure, and instead of moving the liquid gas boundary, there is a liquid gas boundary. The density of liquid and gas is the same and there is no difference between them. Supercritical drying can be used with supercritical fluids and there are several different methods of drying.

The normal drying process involves the use of medium heat or pressure and is fine when applied to substances such as water that is not easily broken. Some substances or equipment - for example, microelectromechanical devices that have small machinery and mdpopel; During this drying process, experience imbalance, because when the surface tension of the liquid changes to gas, it stretches against the structure of the substance. In fine structures, this pulling can cause problems.

To do this with surface tension, supercritical drying is one method that does not affect the skirt limit of liquid gas and does not affect capillary stress of the substance. The capillary voltage is the space between the pores of the fabric and when the liquid becomes a normal way of gas, the capillary voltage causes the collapse of the substance. Supercritical fluid is required. These fluids look like liquids, but are able to expand and compress like gases; They are also able to dissolve other substances. The preparation of these fluids involves saturation of pores with an organic solvent.

There are several ways to perform supercritical drying. In the high -pressure method, the high -temperature method, the pressure chamber is filled with a supercritical fluid and an organic solvent in which the supercritical fluid was immersed. The substance is then rapidly exposed to heat and pressure that exceeds its critical limit, causing the fluid to turn into gas,where the capillary voltage is maintained.

While the high -pressure and high -temperature method is the most common way to perform supercritical drying, there is a low temperature method; This method is safer because the other may be explosive and some substances cannot handle high pressure and heat. Instead of organic solvent, carbon dioxide is used because it is supercritically extracted at low temperature. Supercritical drying with this method is not always successful, as some fluids will react with carbon dioxide to form metal carbonate.