We demonstrated multifunctional electrospun polyelectrolyte fabrics with switchable superhydrophobicity as well as oleophobicity. To produce this smart fabric, we used a strategy that combines electrospinning to fabricate nanofibrous templates with nanopores and a simple coating of the polyelectrolyte that can exchange counterions with various hydration energies. The ion exchange of polyelectrolyte embedded in nanoporous fibrous webs leads to switchable wetting behavior in water and oil. This electrospun fabric was also utilized as chemical filters for the efficient removal of sulfur dioxide (SO2) from waste gas streams.