Described is the application of layer-by-layer (LbL) electrostatic assembly techniques to electrospun nanofibers in order to fabricate novel, breathable electrospun fiber-based chemical and biological detoxifying protective fabrics and filters. The combination of layer-by-layer electrostatic assembly and electrospinning technique allows one to take advantage of high specific surface area, light weight and breathability of electrospun fiber mats while simultaneously providing the versatility to incorporate different functional polyelectrolytes to achieve multifunctional coatings for both chemical and biological protection together. The functionalized fiber mats can be incorporated into breathable chemical and biological protective fabrics, filters and masks. In addition, LbL electrostatic coating of porous non-woven materials provides the versatility to generate multifunctional polymer-based membrane materials for other applications.