A solvent-resistant polymeric membrane comprising a solvent-inert polymer having a solubility parameter greater than 18 (J/cm.sup.3).sup.0.5, such as a polyketone, a polyether ketone, polyarylene ether ketone ketone, a polyimide, a polyetherimide, or a polyphenylene sulfide, is described. The solvent-resistant polymeric membrane can be prepared by methods in which solvent-inert polymers form a solution at room temperature.