The Lotus Effect – Superhydrophobicity/superhydrophilicity
What is the lotus effect?
The lotus effect, or superhydrophobicity, has been known for many years. It is named after the lotus flower that grows in muddy waters, but always seems to look clean. The reason for this is because the lotus leaves contain micro– and nanostructures, something that makes the leaf surface super hydrophobic to water. In other words, when rain drops fall on the leaves, the water peels of and removes dirt and dust.
The structures of the lotus leaf can be mimicked, and recently other structures have been identified to provide superhydrophobic surface properties, e.g. honeycomb structures.
Superhydrophobicity / Superhydrophilicity
In nature, you may find a lot of inspiration when it comes to surface topologies that can alter the hydrophobicity of bulk materials. The lotus flower is a prominent example of how a complex hierarchical topology in combination with a thin wax layer can render the surface of the lotus flowers leaves’ self-cleaning.
Such functional surfaces/structures are gaining more and more attention, because today it is possible to mass-produce many of these structures with techniques, such as injection molding, hot-embossing and roll2roll replication.
Superhydrophobicity and what we can do
NIL Technology has worked on realizing superhydrophobic and self-cleaning polymer surfaces by means of hot embossing and injection molding. This work has resulted in a broad empirical knowledge of the prerequisites for obtaining the desired functionality in a given material and environment, with or without surface treatments, such as molecular deposition if the polymer material is not intrinsically hydrophobic, or if an improved or superior functionality is needed.
NILT has in-house structures that have demonstrated superhydrophobic and self-cleaning properties with cold and hot water as well as more complex fluids.