Superhydrophobic surfaces recently received a lot of attention from all over the world for their water-repelling characteristics and the wide scope of their applications. The next step in this direction was recently taken by a team of researchers working at the Pohang University of Science and Technology i.e. POSTECH. They discovered an eco-friendly and low-cost method of application of the superhydrophobic layers over objects through some commercially available salt particles, water, and polydimethylsiloxane (PDMS).
In the natural environment around us, we always observe ultra hydrophobicity over some specific things such as Lotus leaves. The leaf, actually features some microscopic protrusions over its surface that minimizes adhesion to lowermost level. Resultantly, the water droplets roll over the surface along with any other dirt particle. The effect is normally termed as the ‘lotus effect’. A lot of research has already been carried out in a practical application of the lotus effect over other surfaces. They stimulated the nanoscopic and micro surface architectures to get this effect.
There are several other practical world applications noted for superhydrophobic surfaces such as anti-sticking, anti-icing, as well as self-cleaning characteristics.
Moving a few imaginations ahead, this breeds the idea of stain-repellent clothes or self-cleaning buildings which will all be based on the present day method that we adopt for application of superhydrophobic layer needed to complicate procedures along with some other exorbitant costs of equipment or harsh chemicals. The research team found a solution to this problem with salt-dissolution-assisted etching procedure. They took advantage of the fact that salt dissolves well in water, they exposed a salt particle surface embedded with PDMS to an aqueous surrounding.
The rest of the PDMS surface hardened with nano/micro-hierarchical topography that reaches up to the level of a superhydrophobic surface. The process can also be applied to 3D and large sized surfaces.
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