The invention relates generally to liquid-repellent coatings, and in particular, to porous liquid-repellent coatings, a method of preparing the porous liquid-repellent coatings, and a method of characterizing a porous surface for the liquid-repellent coatings. The invention further relates to a porous liquid-repellent coating comprising a porous layer of a transition metal oxide and/or hydroxide and a layer of a liquid-repellent compound deposited onto the porous layer of the transition metal oxide and/or hydroxide, wherein the porous layer of the transition metal oxide and/or hydroxide is comprised of a plurality of surface pores of varying angles with an average angle that is re-entrant.