Modified PDMS with inserted hydrophilic particles for water harvesting

Abstract Invisible water is viewed as a potential resource for plants grown in deserts. Amphiphilic surfaces with good flexibility and coalescence are desired for water harvesting applications, but they cannot be precisely controlled. Inspired by desert beetles, we present an amphiphilic surface array that can rapidly condense and slide water droplets. The surface consists of a hydrophilic particle array inserted on a hydrophobic substrate of PDMS mixed with graphene powder. SEM images showed that Fe-particles with different dimensions inserted on an amphiphilic surface enabled the formation of hydrophilic islands. The rapid dropping frequency and landing speed tiny drops were due to the presence of more hydrophobic spaces between single hydrophilic spots and the suitable size of hydrophilic spots. We further demonstrated that the Amphiphilic-15 surfaces, due to its suitable hydrophilic spots size matching with favorable hydrophobic space, outperforms hydrophobic, hydrophilic, and other surfaces during water harvesting.