Researchers at North Carolina State University have developed a technique that uses light to get two-dimensional (2-D) plastic sheets to curve into three-dimensional (3-D) structures, such as spheres, tubes or bowls.
The advance builds on earlier work by the same research team, which focused on self-folding 3-D structures. The key advance here is that rather than having the plastic fold along sharp lines -- into polygonal shapes such as cubes or pyramids -- the plastics bend and curve.
Researchers Michael Dickey, a professor of chemical and biomolecular engineering at NC State, and Jan Genzer, the S. Frank and Doris Culberson Distinguished Professor in the same department, were early leaders in the field of self-folding 3-D structures.
In their landmark 2011 paper, the researchers outlined a technique in which a conventional inkjet printer is used to print bold black lines onto a pre-strained plastic sheet. The plastic sheet was then cut into a desired pattern and placed under an infrared light, such as a heat lamp.
The printed lines absorbed more energy from the infrared light than the rest of the material, causing the plastic to heat and contract -- creating a hinge that folded the sheets into 3-D shapes. By varying the width of the printed lines, or hinges, the researchers were able to change how far -- and how quickly -- each hinge folds. The technique is compatible with commercial printing techniques, such as screen printing, roll-to-roll printing, and inkjet printing, that are inexpensive and high-throughput but inherently 2-D.
But now they're using a similar approach to accomplish a very different result.
"By controlling the number of lines and the distribution of ink on the surface of the material, we can produce any number of curved shapes," says Dickey, co-corresponding author of a paper on the self-curving plastics. "All of the shapes use the same amount of ink; it's simply a matter of where the ink is applied on the plastic." Note: video demonstrating the technique can be seen at https:/
"Our work was inspired by nature, because natural shapes rarely incorporate crisp folds, instead opting for curvature," says Amber Hubbard, a Ph.D student at NC State and co-lead author of the paper. "And we found that, in order to make functional objects, we often needed to use a combination of curved and folded shapes.
"Other researchers have developed techniques for creating self-curving materials, but they did this using soft materials, such as hydrogels," Hubbard adds. "Our work is the first attempt to accomplish the same using thermoplastics -- which are stronger and stiffer than the soft materials. That makes them more attractive for use in performing some practical actions, such as gripping an object."
"The materials we're working with also hold their shape, even after the light is removed," says Russell Mailen, a Ph.D student at NC State and co-lead author of the paper. "That's an advantage, because soft materials change shape only when exposed to a solvent, and once they are removed from the solvent they lose their shape."
The researchers have also developed a computational model that can be used to predict the 3-D shape that will be produced by any given printing pattern.
"One of our goals is to fine-tune this model, which Mailen developed," Genzer, co-corresponding author, states. "Ultimately, we'd like to be able to input a desired 3-D shape into the model and have it create a pattern that we can print and produce."
The paper, "Controllable curvature from planar polymer sheets in response to light," is published in the Royal Society of Chemistry journal Soft Matter and was selected by the journal to be featured on the cover. The paper was co-authored by Mohammed Zikry, the Zan Prevost Smith Distinguished Professor of Mechanical and Aerospace Engineering at NC State. The work was supported by the National Science Foundation under grants 1240438 and DGE-1252376.
Matt Shipman | EurekAlert!
High-speed surveillance in solar cells catches recombination red-handed
14.02.2019 | Osaka University
Sodium is the new lithium: Researchers find a way to boost sodium-ion battery performance
04.02.2019 | Nagoya Institute of Technology
For the first time, an international team of scientists based in Regensburg, Germany, has recorded the orbitals of single molecules in different charge states in a novel type of microscopy. The research findings are published under the title “Mapping orbital changes upon electron transfer with tunneling microscopy on insulators” in the prestigious journal “Nature”.
The building blocks of matter surrounding us are atoms and molecules. The properties of that matter, however, are often not set by these building blocks...
Scientists at the University of Konstanz identify fierce competition between the human immune system and bacterial pathogens
Cell biologists from the University of Konstanz shed light on a recent evolutionary process in the human immune system and publish their findings in the...
Laser physicists have taken snapshots of carbon molecules C₆₀ showing how they transform in intense infrared light
When carbon molecules C₆₀ are exposed to an intense infrared light, they change their ball-like structure to a more elongated version. This has now been...
The so-called Abelian sandpile model has been studied by scientists for more than 30 years to better understand a physical phenomenon called self-organized...
Physicists from the University of Basel have developed a new method to examine the elasticity and binding properties of DNA molecules on a surface at extremely low temperatures. With a combination of cryo-force spectroscopy and computer simulations, they were able to show that DNA molecules behave like a chain of small coil springs. The researchers reported their findings in Nature Communications.
DNA is not only a popular research topic because it contains the blueprint for life – it can also be used to produce tiny components for technical applications.
11.02.2019 | Event News
30.01.2019 | Event News
16.01.2019 | Event News
18.02.2019 | Interdisciplinary Research
18.02.2019 | Process Engineering
18.02.2019 | Studies and Analyses