A method of preparing a porous film comprises electrodepositing material from a mixture onto a substrate, the mixture comprising: (I) a source of metal, inorganic oxide, non-oxide semiconductor/conductor or organic polymer; (II) a solvent such as water; and (III) a structure-directing agent such as octaethylene glycol monododecyl ether to form an homogenous lyotropic liquid crystalline phase in the mixture. Electrodepositing the film from a lyotropic liquid phase in this manner provides a porous film having a substantially regular structure and substantially uniform pore size.