“Wrinkle free Nanomechanical Film: Control and Prevention of Polymer Film Buckling”

1/27/2007

According to Nanowerk News,Thats because the same underlying principles of wrinkling lie behind human skin and the polymer film systems which Lee has been investigating. Human skin consists of a thinner outer layer (the epidermis, around 50-100 m thick) resting on top of a thicker layer (the dermis, around 1-3 mm thick) says Lee.
Although skin is a living material, vastly more complicated than a polymer film, Lee believes that both heated film and aged skin wrinkle permanently because they stiffen up more than the soft plastic or dermis below them. The same effect is seen in dried fruits, when thin dried skin stiffens over a soft interior.
Lee and his colleague Troy Hendricks wanted to prevent polymer films from buckling as they were compressed or heated during the manufacturing process. Wrinkled films, Lee told Chemistry World, can be a problem for electronic applications; for instance, the wrinkles can approach the size of the increasingly small features printed on the film, disrupting an electronic devices function. The researchers found that 50 nm silica particles deposited in layers through a thin polyelectrolyte film stopped the film from wrinkling up when heated or compressed. Lee suggests that the particles work by redistributing stress forces out of the plane of the film. The nanoparticles might affect the films performance, Lee conceded; though in the case he tried, the film stayed transparent to light as required. His group are testing different sorts of nanoparticles, of varying size and shape, to see if they have the same anti-wrinkling properties.
There is obvious health and safety issues with such applications - the nanoparticles will have to be cleared for toxicity. Nor may Lees technique be generally applicable, if skin doesnt behave in the same way as thin films do. But its an intriguing possibility: one more cosmetic spin-off to add to nanotechs lengthening list.

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