Electrospun fibrous membranes and uses thereof

A fibrous mat comprising a plurality of fibers, wherein each of the fibers is a porous polymeric fiber comprising an aromatic polymer;

• wherein:
• an average cross-section of the fibers is between 0.5 and 30 um;
• the aromatic polymer is stable at a temperature of at least 200° C.;
• the fibrous mat is characterized by air permeability coefficient of at least 10−13 m2.