Bioinspired triangular patterns for water collection from fog

Cacti use spines with conical geometry to transport water to its base. A conical shape with curvature gradient generates a Laplace pressure gradient along the droplet, which is responsible for droplet motion. In this study, the triangular shape was used which also generates a Laplace pressure gradient along the droplet. A bioinspired surface, composed of a hydrophilic triangular pattern surrounded by a rim of superhydrophobic region, was used to transport water collected from the fog on the hydrophilic pattern. The growing droplets start to coalesce into bigger ones. Eventually, they are big enough to touch the superhydrophobic borders, which trigger the transport motion. Droplet mobility and water collection measurements were made on triangular patterns with various geometries to determine the most efficient configurations. Results from this study can be used to enhance the performance of water collection systems from fog. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology (part 2)'.

Optimization of bioinspired triangular patterns for water condensation and transport

Water condenses on a surface in ambient environment if the surface temperature is below the dew point. For water collection, droplets should be transported to storage before the condensed water evaporates. In this study, Laplace pressure gradient inspired by conical spines of cactus plants is used to facilitate the transport of water condensed in a triangular pattern to the storage. Droplet condensation, transportation and water collection rate within the bioinspired hydrophilic triangular patterns with various lengths and included angles, surrounded by superhydrophobic regions, were explored. The effect of relative humidity was also explored. This bioinspired technique can be used to develop efficient water collection systems. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology (part 2)'.

Water condensation and transport on bioinspired triangular patterns with heterogeneous wettability at a low temperature

Desert beetles and cactus plants collect water from fog in arid regions. The desert beetle uses heterogeneous wettability to transport water to its mouth. A cactus uses conical spines which provide Laplace pressure gradient to transport water to its base. In this study, bioinspired triangular patterns with various wettability and different from the surrounding regions were investigated to transport condensed water from ambient air. A low temperature of 5°C was used to decrease saturated vapour pressure to promote water condensation. Results from this study can be used to enhance the performance of water collection systems. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology'.