provided are methods of treating an open cell polyimide foam product to produce a treated polyimide foam product having a property of repelling water or oil . the method includes the steps of : selecting a polyimide foam product having an external surface area and an open cell structure that has an interior surface area , wetting the exterior surface area and the interior surface area with a chemical treatment fluid comprising a treatment chemical that has a property of repelling water or oil , and distributing the treatment chemical onto at least a portion of the interior surface area sufficient to modify a surface property of the interior surface . also provided are treated polyimide foam products that have an open cell polyimide foam substrate with an interior surface area and a treatment chemical on at least a portion of the interior surface area . the treatment chemical renders the interior surface hydrophobic or oleophobic .