Plasma-aided technique can be used to aid surface impregnation: materials with low surface free energy were subjected to activate plasma pre-treatment to increase the surface free energy. The higher the surface free energy of the solid substrate is, the better the impregnation. In general, the following efficiency criterion was found: “Plasma-aided impregnation of a material will be more successful and the material will be more susceptible as the difference between its surface free energy and the surface tension of the impregnation solution is greater than zero”. If not, there will be impregnation problems.