We demonstrate that miscible and phase-separated fibers of the blend between polystyrene (PS) and poly(vinyl methyl ether) (PVME) can be electrospun by appropriate selection of the solvent Solutions in benzene allow preparing miscible fibers with composition ranging from pure PS to PS/PVME 70/30. Results indicate that the rapid solvent evaporation during electrospinning has no significant influence on the phase behavior of polymer blends when the system is miscible throughout the ternary phase diagram. On the other hand, fibers electrospun from chloroform solutions show a clear phase separation because of a closed immiscibility loop. They are nevertheless highly malleable, la contrast with the brittle films obtained by solution casting. The confinement and solvent evaporation kinetic lead to a core-sheath structure, with the interior composed of the PS-rich phase and the surface highly enriched in PVME, as opposed to microdomains in cast films. The shell can be extracted rapidly and efficiently by a 10 s treatment in water, converting the mat from fully wettable to highly hydrophobic.