A fibrous properties-switching article comprises a mat consisting of fibers having a fiber diameter of 2 microns or less. The fibers comprise a polymer, copolymer, polymer blend, or polymer network, wherein the fibers have a diameter of 2 gm or less. The surface and/or bulk property of the mat changes over a range of temperatures, wherein the polymer, copolymer, polymer blend, or polymer network undergoes a structural change over the range of temperatures. The fiber mat is formed by electrospinning. In an exemplary embodiment, a blend of polystyrene and poly((N-isopropyl acrylamide) (b1-PS/PNIPA) in dimethylformamide (DMF) is electrospun to form a mat consisting of fibers with a diameter less than 2 .mu.m that shows a transition from a superhydrophilic surface to a nearly superhydrophobic surface over a temperature range from 30.degree. C. to 45.degree. C. A fiber mat formed by electrospinning a DMF solution comprising poly(N-isopropyl acrylamide-co-methacylicacid) (PNIPAMAA), comprises fibers having a diameter less than 2 .mu.m and are cross linked after spinning. The crosslinked PNIPAMAA, (x1-PNIPAMAA) fiber mat displays a transition from a hydrophilic surface to a nearly hydrophobic surface over a temperature range from 30.degree. C. to 45.degree. C.
 This invention was made with government support under Contract No. DE-AC04-94AL85000 awarded by the Department of Energy National Nuclear Security Administration. The government has certain rights in the invention.