Due to the high diffusivity of supercritical fluids it is possible to impregnate porous or polymeric media. Using supercritical fluids, impregnation is carried out in two steps. First, the matrix is “soaked” by a supercritical solution of the compound to be impregnated. In the second step, a rapid decompression permits its deposition of the compound while the solvent is rapidly vented in a gas phase. Examples of this concept are:

In this type of technology, Thar Process has successfully developed and industrially implemented a supercritical process to impregnate PTFE membranes with oleophobic chemicals.