There might be few flowers as well-known as the Edelweiss, but few would want to look for this woolly white, Alpine flower for any source of technological inspiration. Now, however, scientist Jean-Pol Vigneron with the University of Namur in Belgium and his colleagues in Budapest, Meise and Stanford think they own found just that.
If the researchers investigated the micro-structure of Edelweiss flowers, last January, these were surprised to discover a peculiar ultra-violet-absorbing structure in the dense white hairs, that go over the complete Edelweiss plant. The hairs are especially abundant around the modified silver-white leaves that from the Edelweiss's "flowers". Vigneron with his fantastic fellow scientists immediately realized that there would certainly be a wide range of commercial purposes of synthetic versions with the structure, but the prospect of really manufacturing Edelweiss-inspired structures seemed remote.
"We discovered that the counter of each and every hair is covered in tiny, regularly spaced fibers, running parallel to one another over the entire leaf hairs," explains Vigneron. "Each fibre is simply 180 millionths of the millimetre across. Because of their small size and highly regular arrangement, these fibres together constructed a structure, which absorbs ultraviolet light. No affect visible light at all because it has longer wavelengths than ultraviolet, so is not disturbed from the structure. With mathematical modeling techniques, we had been able to show that when ultraviolet waves fell about the structure, these folks were guided by it and eventually absorbed, either inside the walls of the hairs or, possibly by a material in the middle of the hairs."
The scientists were able to check their calculations through measurements of precisely how high of the sunlight falling for the silver-white Edelweiss leaves was reflected, and exactly how much was transmitted and undergone them. Affirmed, they found out that almost no in the ultraviolet light falling for the plant was reflected or transmitted, instead, it was just about all absorbed by the hairs since the leaves, in the same way their mathematical model had predicted. The hairs apparently protect the plant leaves beneath them from damaging U.V.A. radiation.
Ultraviolet radiation is best famous for causing sunburn, snow blindness and skin cancer in people, but it also damages a variety of materials, including fabrics, paints and plastics. "Finding ways to absorb damaging ultraviolet radiation is a common engineering problem," comments Prof Vigneron, " and then we were excited to view a plant which includes designed a clever means to fix this. We immediately thought this structure could be very useful for anti-U.V.-coatings for specialist car- and aircraft-paints, as well as sunscreens and anti-U.V. packaging materials. The situation was how to manufacture artificial fibres with such minuscule diameters as those located in the Edelweiss." The scientists soon realized, however, that by copying the Edelweiss structure in glass, they could borrow manufacturing techniques developed to make optics fibres and dramatically simplify the procedure.
Optic fibres are manufactured from large glass rods, called "preforms", a few inches in size and about one inch across, that are stretched ("pulled") at either side until a skinny fibre 10,000 times longer and correspondingly thinner is made. Interestingly, the thin fibres have the same shaped cross-section as the original rod, for an accuracy of a few percent. The study realized it might be simple to copy the actual shape of the Edelweiss fibres and ventured into their partners at the PHLAM laboratory in Lille, France, to debate the technical information on producing prototypes. For that French laboratory ( which is owned by a waveguide-developing company), the scientist's plans have proven surprisingly all to easy to perform and it plans to begin production of some artificial Edelweiss fibres in October.
Currently, most products offering protection against U.V. use tiny spherical "nanoparticles"of Titanium dioxide, which can be effective, but sometimes be hard to set up on a surface. The project organizers hope the synthetic Edelweiss fibres will provide the identical degree of UV protection because nanoparticles but be better to handle.