At the MSU Department of Chemical Engineering and Material Science (East Lansing, Michigan), Lee and Hendricks performed experiments to find ways to prevent thin layers of polymers from buckling while being heated or compressed during the manufacturing process. It is important that polymer films do not wrinkle because they can degrade or even destroy the operation of electronic devices.
Polymers are synthetic compounds of large molecules made of smaller duplicate molecules that are bonded together chemically. Nylon is a common example.
In the manufacturing process, thin films of polymer are routinely applied on top of a thick substrate, such as plastic, to improve the surface characteristics of electronic devices. Improvements that are sought to the surface properties include water-repulsion, anticorrosion, and biocompatibility.
Lee states that when nanoparticles are spread in a thin film on a substrate they help to break up compressive forces that build up when the material is heated or subjected to compression. The nanoparticle thin film keeps (what is called) the ‘critical buckling strain’ to a minimum, thus stopping the buckling of the substrate, but without adversely affecting it. Lee explains, “The wrinkle-free films will automatically absorb or deflect the stress and stay flat, just as they are after formation.”
Nanotechnology is the general term for the control and application of matter on the molecular scale (or nanoscale)—basically less than one micrometer (one-millionth of a meter) and often times at levels of 100 nanometers or smaller (where one nanometer is one-billionth of a meter).
During their study, the researchers deposited 50-nanometer sized silica particles (technically, naturally occurring silicon dioxide, a common example is sand) in layers into a thin polyelectrolyte film. (A polyelectrolyte is an electrolyte with a high molecular weight. A protein is an example.)
As reported in their December 2006 paper “Wrinkle-Free Nanomechanical Film: Control and Prevention of Polymer Film Buckling” in the Nano Letters of the American Chemical Society, the introduction of nanoparticles stops the film from wrinkling when heated or compressed.
While performing their experiment, the two researchers imagined that the human skin could be similar to polymer film. Thus, skin might act in a similar way when tiny nanoparticles are applied to the skin that it is just starting to wrinkle at the nanoscale level. Even though skin is much more complicated, both heated/compressed film and aged skin wrinkle permanently because they harden more than the soft foundation layer of plastic (for substrates) or dermis (the layer of skin beneath the top epidermis layer), respectively.
Lee added, “Everything starts at a really small scale, so if we can prevent the buckling at the very beginning—at the nano level—we can eliminate large scale wrinkles.”
The idea proposed by Lee and Hendricks is still in the very early research stage. Safety and health concerns must first be identified and solved. However, if their idea is developed into practical procedures and products, it could bring about a cosmetic way to prevent (or, at least, minimize) wrinkles from appearing.
It is a big idea based on very tiny nanoparticles.
For further information about the research being performed at the Department of Chemical Engineering and Materials Science (Michigan State University), go to: http://www.chems.msu.edu/dept.research.htm.
For a simple explanation on nanoparticles and why they are becoming very important to manufacturing, go to: http://www.malvern.com/LabEng/industry/nanotechnology/nanotechnology_definition.htm.