Personal introduction
In every sciencefiction movie you'll find lasers. Most often in the form of a laser-sword or a gun. With a 'pew' or a 'dzing' the laserbeam passes by and causes a massive explosion, opening the 'door' for the next scene. To bad you can't see light when it passes by. To be able to see light it needs to hit your eye and with these lasers it is most certainly deadly for everybody outside of Hollywood.
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Let me introduce myself, my name is Edwin Kroon, a scientist and you might want to reconsider watching a movie with me.
I love efficiency, while writing this there are 2 lasers working hard so I'm putting 3 hours of work in just one. This is (bio)logical, nature does this all the time. A simple bird feather for instance: it insulates very well, aerodynamically optimized, water repellent, sturdy and 'painted' in camouflage.
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That has baffled me from the moment I learned feathers and hairs are both made from the same material: keratine. Where hair attracks water, feathers repell it. So water repellent (hydrophobic, hydro=water, fobic=te fear/repell) is a not a material-property, hairs and feathers react differently, but is caused by the surface structure.
Which implies that something can be made water repellent, or water attracting, by changing the surface structure on a miniature scale.
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And if this works on water, could a different structure do the same with oil and fats? Or snow, like pinguinfeathers?
Education to practice
During the education as an Animal Scientist at the Wageningen University I learned that this micro- and nano-structures are responsible for many neat features. The microscopic hairs under the feet of a Gecko to make it stick, razorsharp barbs on butterflywings kill bacteria, with slats in between to create the illusion of a colour. Or the anti-fogging properties of mosquito-eyes!
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If these structures could be replicated and put to use, that could potentially change the world. But at least improve my life, a water-repelling shower drain would hopefully never clock up ever again. See here my effiency kicking in, achieving more by doing less.
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A laser is the very first tool I encountered that allowed me to replicate structures on this scale on every day materials like metals and plastics. As long as I can recreate the correct bumps and ridges at the same scale. See the section Research for achieved examples.
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The challenge from working at the scale of thousands or millionth of a millimeter is that even the slightest inaccuracy can ruin the desired effect of the nano-stucture. After all, in 1 single millimeter there should be thousands or millions of identical bumps and ridges to make the structure work.
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I am still amazed that a laser can do this and I'm proud that I can find the correct laser-settings to copy nature.
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But I'm humbled every time I look outside, see the simplest of insects with multi-layered micro- and nano-structures and realize that at least 50% of the laser-applications and nanostructuers are still unknown.
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(Photo credit: wikimedia commons; MichaD; Peacockbutterfly, Aglais io)
