Scientist cook up a cooler way to produce polyethylene thin films.

One would pretty much have to be living under a rock in a developed nation to not have encountered polyethylene. The chains of ethylene or ethene monomers comprise a vast amount of products, from the ubiquitous plastic bag to film to implants. PE comes in various forms and densities and over 60 million tons of the material are produced yearly.

Though the production of PE is not particularly difficult in bulk, making ultra-thin films of the polymer have been notably more time and energy consuming. Typically, engineers create a dilute solution from an organic solvent and the polymer. To break up the crystalline structure of the polymer, heat must be applied to the solution. The solution can then be applied to a surface and the film forms when the solvent is cooled or removed.

A new method, devised by scientists at the University of Konstanz, removes the need for heating to dissolve the polymer into a solution by creating an aqueous solution of nanoscale crystals from the start. The catalyzation process involves ethylene and nickel complexes and produces crystals of about 25nm by 6nm in size.

To produce the film, droplets of the solution are applied to glass slides which are spun at 2,000 revolutions per minute. The spinning process removes the non-polymer substances. When all is said and done, a thin film of about 50nm in thickness is left behind.

The key to this technique lies in an amorphous, or non-crystalline, layer of PE on each of the crystals. Though the coating measures about 1nm in thickness, the interaction between each crystal's is very strong, holding the crystals in place while under the effects of the high speed spin.

Ultra-thin polymer coatings, especially polymers like polyethylene, which are completely harmless and environmentally inert, could be used for vast array of technologies from medical to electronics. Thin polymer films are already under investigation for uses in applications like bacterial growth prevention and incredibly durable rechargeable batteries.

Source from DailyTech