Skip to main content

Flat polymer sheets bend themselves into 3D shapes - just add water



When the petal of a flower is being formed, its shape is achieved by cells in one area expanding more than cells in an adjacent area. This uneven expansion causes the material to buckle, creating the desired curves and creases. Scientists from the University of Massachusetts, Amherst have taken that same principle, and applied it to flat polymer gel sheets that fold themselves into three-dimensional shapes when exposed to water. Some day, such sheets could serve a number of useful purposes.
The researchers use a photolithography process, in which parts of each sheet are masked with a thin painted-on coating, followed by an exposure to ultraviolet light. The polymer that is masked from the UV light will uniformly expand like a sponge when exposed to water. In areas that aren't masked, however, the UV light causes the molecules within the polymer to become cross-linked. This means that the material in those areas will only experience limited expansion when water is added.
When areas with cross-linked molecules are flanked by areas of the protected polymer, buckling will occur as the one area expands more than the other. By strategically patterning the size and placement of the cross-linked areas, along with subjecting some of them to a second UV exposure, the scientists have been able to determine what 3D shapes the sheets would expand into when wetted.
So far, they've managed to create basic shapes such as spheres, saddles and cones. Down the road, however, the researchers believe that the technology could be used in fields such as biomedicine, where cultured cells could be designed to form themselves into blood vessels or specific organs. It could also find use in applications such as robotics, and tunable micro-optics.
It's reminiscent of research recently performed at North Carolina State University, in which black stripes were printed onto pre-stressed flat sheets of polymer. When subjected to infrared light, the striped areas absorbed more energy than the surrounding material. This caused the underlying polymer to contract, which in turn caused the sheets to fold themselves into 3D structures.
A paper on the University of Massachusetts research was recently published in the journal Science.

Comments

Popular posts from this blog

10 URLs to Find Out What Google Knows About You

Google is much more than just a search giant. It is also home to many of your favorite products: Gmail, YouTube, and Chrome, just to name a few. Apart from that, it also offers many products to help you  keep track of your data . Most of these are  hidden deep  inside the My Account dashboard, which many users don’t really know of. These hidden tools  may reveal interesting details  about your usage of Google’s many services. We’ve compiled a list of important Google URLs of some  hidden tools  that carry information of what you did with Google, mostly from the searches that you have made on their many products, the voice searches and typed out Google searches that you have made. Are you ready to  find out what how Google knows about you ? 1.  Google Dashboard Google Dashboard offers  transparency and control over the personal data stored with your Google Account. You can  view  and  manage the data gener...

Nine government sites hit by cyber attacks: NIC

The National Informatics Center (NIC) has revealed that as many as nine government websites were defaced by recent cyber attacks. The center further said that the servers, which hosts these government sites, suffer a number of hacking attempts on a daily basis. The websites www.kumbh2010haridwar.gov.in, www.ueppcb.uk.gov.in, www.gov.ua.nic.in/ujn, www.cdodoon.gov.in, www.arunachal.nic.in,www.bee-india.nic.in, www.civilsupplieskerala.gov.in, www.mpcb.gov.in and www.informatics.nic.in were  defaced , prompting authorities to  ramp up  the cyber security safeguards. In an RTI reply, the NIC, which reports to the Ministry of Communications and Information Technology, said that it was impossible for the body to accurately quantify these attacks but they are usually blocked by security controls put in place. The Ministry was asked to provide details of hacking attempts made on the governments websites in the last ten years (2001-11) along with url names of the portal...

Solar car hits U.S. in round-the-world jaunt

Last October, the SolarWorld GT solar-powered car set out from Darwin, Australia on a drive around the world. It has since driven 3,001 kilometers (1,865 miles) across Australia, logged 1,947 km (1,210 miles) crossing New Zealand and been shipped across the Pacific Ocean. This Friday, it will embark on the U.S. leg of its journey, as it sets out across America from the University of California, Santa Barbara.   The SolarWorld GT is the result of a collaboration between solar panel manufacturer SolarWorld, and Bochum University of Applied Sciences in Germany. The four-wheeled, two-door, two-seat car gathers solar energy through photovoltaic panels built into its roof, with its solar generator offering a peak performance of 823 watts. Custom hub motors are located in both of the front wheels. The vehicle manages an average speed of 50 km/h (31 mph), with a claimed top speed of 100 km/h (62 mph). In order to demonstrate that solar powered cars needn't be a radical...