By: Derek McCurry

 The Lotus effect refers to the very high water repellency exhibited by the leaves of the lotus plant  Allows for self-cleaning, where dirt particles are picked up by passing water droplets due to the architecture of the leaf surface which minimizes adhesion  Main purpose is for protection against pathogens (fungi/algae) Pathogens Dirt particles

 The leaves of the lotus plant are superhydrophobic  Superhydrophobic simply means the surface is very difficult to wet due to the contact angle of the water droplet with the surface  Contact angle: ≥ 150˚  Roll-off angle: <10 ˚ Contact angle Ѳ

 The free energy transfer of non-polar solvent to aqueous solvent is often used to quantify the hydrophobic effect ∆G = H - ∆ TS > O  Hydrophobic effect is entropy-driven at room temperature (H = zero)  Heat capacity change in transfer is positive, whereas it is negative for hydrophilic molecule C p > O O< O

 Nanotechnologists have developed surfaces that can remain dry and clean themselves similar to the lotus leaf including;  Treatments  Coatings  Paints  Roof tiles  Fabrics  Flying insects  Butterflies  Dragonflies  Self-cleaning glass  Protection against concrete corrosion  Anti-snow sticking