Transmaterial

Microparticles

It's maybe a bit too expensive to use for the baubles on a Christmas tree, but it's already available for car owners who like to "be different": a paint that shimmers in a myriad of colors like an oil slick on a wet road. The appearance of all the colors of the rainbow is created by the interference pattern of extremely thin films applied to minute flakes. These microparticles measure less than a tenth of a millimeter across. The special properties of these tiny particles make them increasingly popular, because they can give products undreamed-of capabilities.

Microparticles are used to give many materials additional, unusual properties: like the screws that stick fast when they are tightened, because the thread is coated with microcapsules containing adhesive. A familiar product is the carbonless paper used for multiple copies of forms - they contain minute encapsulated particles of ink. There are plastics with incorporated hard microparticles, which can be shaped like any other plastic but offer unusual resistance to impact. In medicine, capsules of drugs containing particles of iron can be directed to the place where they are to act by means of magnetic fields.

Altogether, experts estimate that the world market for micro-encapsulated products is worth around five billion US dollars per year. But numerous problems have to be solved before a product can go into mass production: What powders can be obtained by drying a very finely sprayed suspension? What methods can be used to create crystals of precisely uniform size from an emulsion, i.e. minute droplets suspended in a liquid? Which reactive resins or plastics are the most suitable for use in the encapsulation of microparticles? Answering these questions calls for highly advanced expertise in chemistry and process engineering. Professor Rolf Kümmel of the Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT explains: "We use computer simulations to analyze the behavior of the microparticles. This helps us to understand the finer details of what happens during various manufacturing processes." [Excerpted from the Fraunhofer Institute website.]

posted by Blaine @ 5:08 PM