My watch list
my.chemeurope.com  
Login  

Self-folding origami

Chemical "programming" to induce Nafion foil to fold itself

26-Jun-2017

© Wiley-VCH

Plastic with a thousand faces: A single piece of Nafion foil makes it possible to produce a broad palette of complex 3D structures. Researchers describe how they use simple chemical "programming" to induce the foil to fold itself using origami and kirigami principles. These folds can be repeatedly "erased" and the foil can be "reprogrammed".

We have all seen the cranes and lotus flowers produced from a sheet of paper by practiced hands. Origami is the traditional Japanese art of folding that transforms paper into complex three-dimensional structures without the use of adhesive. Kirigami is a related technique in which the paper is strategically cut before folding. Both of these techniques have found application in modern technology.

Adebola Oyefusi and Jian Chen from the University of Wisconsin - Milwaukee (USA) have now presented a new variation on this technique. They chemically "programmed" Nafion foil so that heat causes it to fold itself into complex three-dimensional forms. The foil can also be "deprogrammed". Nafion is a polymer that can "remember" its shape, so that a stretched piece of foil will return to its initial form upon heating.

The secret to this trick is this: Nafion can be protonated in an acidic environment and deprotonated in a basic one. When protonated, stretched Nafion shrinks at temperatures over 100 °C, when deprotonated it must be heated over 260 °C. As long as the temperature remains within this range, only regions of the Nafion that are protonated will shrink. The deprotonated Nafion is "locked" and does not shrink. The researchers make use of this by programing the information required for folding in the form of a pattern of "unlocked" regions in a stretched piece of Nafion foil that has been "locked" with potassium hydroxide. The pattern is „painted" onto the sheet using hydrochloric acid. When heated above 100 °C, the sheet shrinks in the region of the lines and folds itself along these "creases".

The scientists made some simple and some complex structures, such as a bird and a zigzag rip pattern common in technical practice; solar panels for satellites, for example, are transported in a folded way and can be spread in just one movement. Simple acid-base chemistry and heating "erased" the structures and the nafion sheets could be coded and folded in a new fashion.

The 3D structures made from Nafion can be used as a master mold. This can be used to cast a secondary mold from plastics like polydimethylsiloxane, which can then be used to make molded components from a wide variety of materials, including polymers, ceramics, or metal. The reprogrammable master molds save time, money, and waste because they can be directly reused without a costly recycling process.

Facts, background information, dossiers
  • ionomers
More about University of Wisconsin-Milwaukee
  • News

    New research paves the way for nano-movies of biomolecules

    An international team, including scientists from DESY, has caught a light sensitive biomolecule at work with an X-ray laser. The study proves that X-ray lasers can capture the fast dynamics of biomolecules in ultra slow-motion, as the scientists led by Prof. Marius Schmidt from the Universi ... more

    Using strain to tune a new quantum material

    Research into a recently discovered class of materials shows they have the necessary characteristics to develop ultra-energy efficient electronics. Topological insulators (TI) are three-dimensional materials that conduct electricity on their surfaces, while the interior insulates. Their sur ... more

    Novel optical fibers transmit high-quality images

    After having recently discovered a new way to propagate multiple beams of light through a single strand of optical fiber, engineers at the University of Wisconsin-Milwaukee (UWM) now have found that their novel fiber architecture can transmit images with a quality that is comparable or bett ... more

More about Wiley-VCH
  • News

    Tailored Polymers from a Printer

    An ever-growing number of coatings, including varnishes and printing inks, as well as tooth fillings, are cured with light. Yet, homogenous, tailored, polymer networks cannot be produced, and the materials tend to be brittle, which limits the use of photopolymers in applications like 3D pri ... more

    Organic Crystals Twist, Bend, and Heal

    Crystals are brittle and inelastic? A novel class of smart, bendable crystalline organic materials has challenged this view. Now, scientists have engineered a molecular soft cocrystalline structure that bends and twists reversibly and without disintegration when stimulated by high temperatu ... more

    Anthracenes orbiting fullerenes

    Saturn is the second largest planet in our solar system and has a characteristic ring. Japanese researchers have now synthesized a molecular “nano-Saturn”. As the scientists report, it consists of a spherical C60 fullerene as the planet and a flat macrocycle made of six anthracene units as ... more

  • Companies

    Wiley-VCH Verlag GmbH & Co. KGaA

    Wiley-VCH publishes monographs, textbooks, major references works and journals in print or online. Wiley-VCH can look back on over 80 years of publishing in chemistry, materials sciences, physics and the life sciences. more

Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE