Abstract: The disclosure relates to omniphobic surface coatings including a solution of fluor-modified polymer and crystalline and/or semi-crystalline polymer and/or inorganic nanoparticles. The disclosure further relates to biphilic substrate surfaces for heat exchangers, including 50-95% of the surface showing a first solid-liquid contact angle and 5 to 50% of the surface showing a second solid-liquid contact angle, wherein the second liquid-solid contact angle is at least 10° higher than first liquid-solid contact angle, and the surface area of second contact angle includes a multitude of discrete surface areas of second contact angle dispersed over the substrate surface.