The primary function of the plant cuticle is as a water permeability barrier that prevents evaporation of water from the epidermal surface, and also prevents external water and solutes from entering the tissues. In addition to its function as a permeability barrier for water and other molecules (prevent water loss), the micro and nano-structure of the cuticle have specialised surface properties that prevent contamination of plant tissues with external water, dirt and microorganisms. Aerial organs of many plants, such as the leaves of the sacred lotus ("Nelumbo nucifera") have ultra-hydrophobic and self-cleaning properties that have been described by Barthlott and Neinhuis (1997). The lotus effect has applications in biomimetic technical materials.