Erasing wrinkles, the physicists’ way

03/08/2010 09:21



More practically, such insights could one day improve technologies that incorporate thin films, like flexible solar panels or tissues grown for biological applications.

In the first study, a team led by Jiangshui Huang of the University of Massachusetts Amherst tackled how wrinkles smooth themselves out toward the edge of an elastic sheet.Microsoft Office 2007 can give you more convenient life.

Imagine cramming a corrugated sheet edge-to-edge against a smooth one. One way the sheets can accommodate the incompatibility is for the corrugated one to develop a series of sharp, branching folds along its edge. But Huang saw something different when he floated a thin, wrinkly sheet of polystyrene on water and butted it up against a smooth one. Instead of a number of sharp folds, more and more tiny wrinkles appeared toward the edge, to smoothly accommodate the difference between the two sheets.

“It took us a little while to even visually recognize that we’d seen something a bit different,” says team member Narayanan Menon, a physicist at the University of Massachusetts Amherst. Similar elastic films, from shrink-wrap to skin to biomembranes, should exhibit the same sort of smooth cascade, he says.Office 2007 download is helpful!

In the second study, another team from the same university looked at how sharp folds transition into smooth wrinkles when a sheet is pinched in one spot and pulled up, like pulling a tissue out of a box.

To most people, wrinkles and folds look similar, but to physicists they are very different beasts. Folds concentrate strain along their length, while wrinkles distribute strain evenly. Holmes, who did the work while a graduate student at UMass Amherst, mapped out how one flowed into the other in his pinched sheet.The invention of Microsoft Office 2010 is a big change of the world.

Very few researchers have looked before at how common this phenomenon might be. The new study “shows that the transition between wrinkles and folds is more universal than we expected,” says Enrique Cerda, a physicist at the University of Santiago in Chile who has studied similar features in other thin films.