Electrospun fiber mats: Transport properties

Early performance measurements on experimental electrospun fiber mats compare favorably with transport properties of textiles and membranes currently used in protective clothing systems. The electrospun layers present minimal impedance to moisture vapor diffusion required for evaporative cooling. Moisture sorption and transport are also important for catalytic hydrolysis of chemical agents in reactive fabric layers. Air flow resistance measurements and electron microscopy suggest that pore size is small enough to exclude aerosol particles. These encouraging results point towards more intriguing questions such as: what is the pore size distribution in these layers, and how will manufacturing processes affect pore size and function? How will the incorporation of reactive solids in the fibers affect transport properties? Can the effect of fiber chemical composition on transport properties be reliably predicted (e.g., hygroscopic fibers will swell and decrease pore size). Once these fundamental effects are understood, a well- defined and tailorable membrane-processing technique will be available for development. Potential future applications of electrospun layers include direct application of membranes to garment systems, eliminating such costly manufacturing steps as laminating and curing. It may be possible to electrospin fibers directly onto 3-D screen forms obtained by 3-D body scanning. Scientists can use a laser-based optical digitizing system to record the surface coordinates of a soldier's body. This information could be integrated with computer-aided design and manufacturing processes to allow electrospun garments to be sprayed onto the digitized form, resulting in custom-fit, seamless clothing.; Water vapor diffusion and gas convection properties of electrospun fiber mats were determined. The fluxes of gas and water vapor transported through the test sample was measured by measuring the temperature, water vapor concentration, and flow rates of the gas leaving the cell. The electrospun layers exhibited minimal impedance to moisture vapor diffusion required for evaporative cooling. Moisture sorption and transport were also important for catalytic hydrolysis of chemical agents in reactive fabric layers. The pore size was small enough to exclude aerosol particles as observed by air flow resistance measurements and electron microscopy. The fiber mats compare favorably with the transport properties of textiles and membranes currently in use.