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| Lotus leaf and self-cleaning surfaces | |
| The anatomical principles behind the self-cleaning surface of the Lotus leaf (Nelumbro nucifera) area being used to create self-cleaning surfaces in plastic and other materials for many applications including consumer products such a plastic cups. The surface of a Lotus leaf consists of many tiny pillars with a wax layer on top. Water is lifted by these pillars and forms into spherical droplets. These droplets cannot cover the leaf surface. Dirt particles are removed as these water droplets roll off the leaf having had no opportunity to stick to the surface. Scientists at the University of Twente, Enschede, the Netherlands, have created similar surfaces by bombarding them with ultra-fast lasar pulses in two phases. In the first phase, the surface gets a fine rippled pattern. The second phase consists of creating an array of pillars. These pillars have the fine pattern caused by the first step. The result is that water forms into droplets just as in the Lotus leaf but in the absence of a layer of wax. The work is being applied to micro-machine injection moulds from which to produce these sculptured surfaces on cheap polypropylene and other polymer products that have the same self-cleaning properties. These new surfaces feel silky to the touch. “Alphagalileo”. Further information: University of Twente. E-mail: max.groenendijk@utwente.nl www.wa.ctw.utwente.nl/research/laser/groenendijk.doc/index.html |
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