Figure: a) Prototype built for on-field study of the absorption characteristics of the hydrogel. The prototype device floating on the sea surface with b) and without c) the aluminum cover. The inset image in (b) shows a zoomed photograph of the device fitted with an aluminum foil cover to prevent direct sunlight irradiation on the hydrogel. d) Cross-sectional view of the prototype. e) Plot showing the temperature increase in the glass substrate and the chamber between the hydrogel and the sponge with and without the cover. f) Relative humidity measurements in the chamber between the sponge and the hydrogel. g) Schematic of the setup used for water harvesting from the saturated hydrogel. h) Setup used for water harvesting. i) Digital photograph showing the water droplets condensed along the side walls. j) Digital photograph of the side wall of the glass container showing uniform condensation of water droplets.