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Want a ‘Shrinky Dinks’ approach to nano-sized devices? Try hydrogels

High-tech shrink art may be the key to making tiny electronics, 3-D nanostructures or even holograms for hiding secret messages.

A new approach to making tiny structures relies on shrinking them down after building them, rather than making them small to begin with, researchers report in the Dec. 23 Science.

The key is spongelike hydrogel materials that expand or contract in response to surrounding chemicals (SN: 1/20/10). By inscribing patterns in hydrogels with a laser and then shrinking the gels down to about one-thirteenth their original size, the researchers created patterns with details as small as 25 billionths of a meter across.

At that level of precision, the researchers could create letters small enough to easily write this entire article along the circumference of a typical human hair.

Biological scientist Yongxin Zhao and colleagues deposited a variety of materials in the patterns to create nanoscopic images of Chinese zodiac animals. By shrinking the hydrogels after laser etching, several of the images ended up roughly the size of a red blood cell. They included a monkey made of silver, a gold-silver alloy pig, a titanium dioxide snake, an iron oxide dog and a rabbit made of luminescent nanoparticles.

two red dragons made from hydrogels
These two dragons, each roughly 40 micrometers long, were made by depositing cadmium selenide quantum dots onto a laser-etched hydrogel. The red stripes on the left dragon are each just 200 nanometers thick.The Chinese University of Hong Kong, Carnegie Mellon University

Because the hydrogels can be repeatedly shrunk and expanded with chemical baths, the researchers were also able to create holograms in layers inside a chunk of hydrogel to encode secret information. Shrinking a hydrogel hologram makes it unreadable. “If you want to read it, you have to expand the sample,” says Zhao, of Carnegie Mellon University in Pittsburgh. “But you need to expand it to exactly the same extent” as the original. In effect, knowing how much to expand the hydrogel serves as a key to unlock the information hidden inside.  

But the most exciting aspect of the research, Zhao says, is the wide range of materials that researchers can use on such minute scales. “We will be able to combine different types of materials together and make truly functional nanodevices.”

Source link In recent years, researchers have been looking for ways to develop nano-sized devices. Now, a new approach known as ‘Shrinky Dinks’ is offering an intriguing solution. It involves using hydrogels to shrink items down to nano-level size while retaining their original characteristics.

Hydrogels are a unique type of polymer with a wide array of applications. It’s composed of a network of cross-linked molecules, and it can be used in a variety of ways. One of its more interesting uses is as a way to shrink items down to nano-level size.

The process for creating nano-sized devices involves using a hydrogel matrix to reduce the size of a device. The hydrogel is applied to the device, which is then exposed to a combination of temperature and pressure. This triggers the hydrogel to contract, shrinking the size of the device.

The hydrogels used in this process are both flexible and robust. This allows them to shrink down items while maintaining their basic characteristics, such as shape and size. As a result, researchers can create incredibly small devices with all of the same properties as their larger counterparts.

The use of hydrogels offers a number of benefits over traditional ‘Shrinky Dinks’ methods. With the hydrogels approach, scientists can reduce the size of a device far more precisely than with other methods. This translates into smaller and more consistent devices that can be used in a variety of applications.

The applications for hydrogels have been growing quickly in recent years. It’s being used in everything from drug delivery systems to nanobots and other nano-devices. And now, thanks to this ‘Shrinky Dinks’ approach, it’s possible to reduce the size of devices and create even smaller and more efficient items.

It’s an exciting area of research, and it’s one that promises to change the way nano-sized devices are created. With the help of hydrogels, scientists can now shrink items down to nano-level size, while still maintaining all of their original characteristics. It could be just what’s needed to push this field forward and help create the next generation of tiny devices.

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