Protective treatment for porous materials

A method for treating a surface of a porous material in an environment, comprising:

• i. setting a temperature of a surface of a porous material to a value T1 and setting a pressure of an environment to a value P1;
• ii. contacting the surface with a fluid having a solidifying temperature at the pressure value P1 above the temperature value T1 and having a vaporizing temperature at the pressure value P1 below 80° C., thereby solidifying the fluid in pores of the material, thereby sealing the pores;
• iii. treating the surface by an etching of the surface or by a modification of the surface;
• and
• iv. setting the temperature of the surface to a value T2 and setting the pressure of the environment to a value P2 in such a way as to vaporize the fluid, whereby a treated porous material is obtained;
• wherein:
• the step i precedes the step ii, the step ii precedes the step iii, and the step iii precedes the step iv, or
• the step i precedes the step ii, the step ii overlaps or is simultaneous with the step iii, and the step iii precedes the step iv, or
• the step ii precedes the step i, the step i precedes the step iii, and the step iii precedes the step iv.