Desorption of Water Collected on Hygroscopic Polymer Nanofibers

The high surface area-to-mass ratio make nanofibers an optimal material structure for water absorption from humid ambient air. Water molecules were concentrated on the surface of hygroscopic nanofibers. Strong nanofibers withstood the forces from the flowing air that carried water molecules to within about 100 nm of the fiber surfaces. Nanofiber surfaces became saturated with water molecules. Microwave energy with frequency of 2.45 GHz caused rapid evaporation and formation of a bolus of steam in the air stream. The bolus was collected and the water condensed in an external condenser. Alternatively, high voltage DC was applied to two edges of a thin mat of hygroscopic nanofiber to evaporate water from the nanofiber mat. The apparatus provides a useful method to test water absorption ability of different hygroscopic nanofibers. It also provides other information needed to design large scale water collectors.