Tag Archives: kirigami

Growing electronics on trees

An April 26, 2022 news item on phys.org caught my eye with its mention of nanocellulose, trees, and electronics,

Electronics can grow on trees thanks to nanocellulose paper semiconductors

Semiconducting nanomaterials with 3D network structures have high surface areas and a lot of pores that make them excellent for applications involving adsorbing, separating, and sensing. However, simultaneously controlling the electrical properties and creating useful micro- and macro-scale structures, while achieving excellent functionality and end-use versatility, remains challenging. Now, Osaka University researchers, in collaboration with The University of Tokyo, Kyushu University, and Okayama University, have developed a nanocellulose paper semiconductor that provides both nano−micro−macro trans-scale designability of the 3D structures and wide tunability of the electrical properties. Their findings are published in ACS Nano.

Cellulose is a natural and easy to source material derived from wood. Cellulose nanofibers (nanocellulose) can be made into sheets of flexible nanocellulose paper (nanopaper) with dimensions like those of standard A4. Nanopaper does not conduct an electric current; however, heating can introduce conducting properties. Unfortunately, this exposure to heat can also disrupt the nanostructure.

The researchers have therefore devised a treatment process that allows them to heat the nanopaper without damaging the structures of the paper from the nanoscale up to the macroscale.

Caption: Schematic diagram of the preparation of the wood nanocellulose-derived nano-semiconductor with customizable electrical properties and 3D structures Credit: 2022 Koga et al. Nanocellulose paper semiconductor with a 3D network structure and its nano−micro−macro trans-scale design. ACS Nano

An April 28, 2022 Osaka University news release (also on EurekAlert), which originated the news item, provides more detail about the work

“An important property for the nanopaper semiconductor is tunability because this allows devices to be designed for specific applications,” explains study author Hirotaka Koga. “We applied an iodine treatment that was very effective for protecting the nanostructure of the nanopaper. Combining this with spatially controlled drying meant that the pyrolysis treatment did not substantially alter the designed structures and the selected temperature could be used to control the electrical properties.”

The researchers used origami (paper folding) and kirigami (paper cutting) techniques to provide playful examples of the flexibility of the nanopaper at the macrolevel. A bird and box were folded, shapes including an apple and snowflake were punched out, and more intricate structures were produced by laser cutting. This demonstrated the level of detail possible, as well as the lack of damage caused by the heat treatment.

Examples of successful applications showed nanopaper semiconductor sensors incorporated into wearable devices to detect exhaled moisture breaking through facemasks and moisture on the skin. The nanopaper semiconductor was also used as an electrode in a glucose biofuel cell and the energy generated lit a small bulb.

“The structure maintenance and tunability that we have been able to show is very encouraging for the translation of nanomaterials into practical devices,” says Associate Professor Koga. “We believe that our approach will underpin the next steps in sustainable electronics made entirely from plant materials.”

About Osaka University

Osaka University was founded in 1931 as one of the seven imperial universities of Japan and is now one of Japan’s leading comprehensive universities with a broad disciplinary spectrum. This strength is coupled with a singular drive for innovation that extends throughout the scientific process, from fundamental research to the creation of applied technology with positive economic impacts. Its commitment to innovation has been recognized in Japan and around the world, being named Japan’s most innovative university in 2015 (Reuters 2015 Top 100) and one of the most innovative institutions in the world in 2017 (Innovative Universities and the Nature Index Innovation 2017). Now, Osaka University is leveraging its role as a Designated National University Corporation selected by the Ministry of Education, Culture, Sports, Science and Technology to contribute to innovation for human welfare, sustainable development of society, and social transformation.

Here’s a link to and a citation for the paper,

Nanocellulose Paper Semiconductor with a 3D Network Structure and Its Nano–Micro–Macro Trans-Scale Design by Hirotaka Koga, Kazuki Nagashima, Koichi Suematsu, Tsunaki Takahashi, Luting Zhu, Daiki Fukushima, Yintong Huang, Ryo Nakagawa, Jiangyang Liu, Kojiro Uetani, Masaya Nogi, Takeshi Yanagida, and Yuta Nishina. ACS Nano 2022, XXXX, XXX, XXX-XXX DOI: https://doi.org/10.1021/acsnano.1c10728 Publication Date:April 26, 2022 © 2022 The Authors. Published by American Chemical Society

The paper appears to be open access.

A robot that morphs from a ground vehicle to an air vehicle using liquid metal

This video starts slow but the part where the robot morphs is pretty good stuff,

A February 9, 2022 news item on ScienceDaily announces a new approach to shape-changing materials,

Imagine a small autonomous vehicle that could drive over land, stop, and flatten itself into a quadcopter. The rotors start spinning, and the vehicle flies away. Looking at it more closely, what do you think you would see? What mechanisms have caused it to morph from a land vehicle into a flying quadcopter? You might imagine gears and belts, perhaps a series of tiny servo motors that pulled all its pieces into place.

If this mechanism was designed by a team at Virginia Tech led by Michael Bartlett, assistant professor in mechanical engineering, you would see a new approach for shape changing at the material level. These researchers use rubber, metal, and temperature to morph materials and fix them into place with no motors or pulleys. The team’s work has been published in Science Robotics. Co-authors of the paper include graduate students Dohgyu Hwang and Edward J. Barron III and postdoctoral researcher A. B. M. Tahidul Haque.

A February 9, 2022 Virginia Tech news release (also on EurekAlert) by Alex Parrish, which originated the news item, provides more detail,

Getting into shape

Nature is rich with organisms that change shape to perform different functions. The octopus dramatically reshapes to move, eat, and interact with its environment; humans flex muscles to support loads and hold shape; and plants move to capture sunlight throughout the day. How do you create a material that achieves these functions to enable new types of multifunctional, morphing robots?

“When we started the project, we wanted a material that could do three things: change shape, hold that shape, and then return to the original configuration, and to do this over many cycles,” said Bartlett. “One of the challenges was to create a material that was soft enough to dramatically change shape, yet rigid enough to create adaptable machines that can perform different functions.”

To create a structure that could be morphed, the team turned to kirigami, the Japanese art of making shapes out of paper by cutting. (This  method differs from origami, which uses folding.) By observing the strength of those kirigami patterns in rubbers and composites, the team was able to create a material architecture of a repeating geometric pattern.

Next, they needed a material that would hold shape but allow for that shape to be erased on demand. Here they introduced an endoskeleton made of a low melting point alloy (LMPA) embedded inside a rubber skin. Normally, when a metal is stretched too far, the metal becomes permanently bent, cracked, or stretched into a fixed, unusable shape. However, with this special metal embedded in rubber, the researchers turned this typical failure mechanism into a strength. When stretched, this composite would now hold a desired shape rapidly, perfect for soft morphing materials that can become instantly load bearing.

Finally, the material had to return the structure back to its original shape. Here, the team incorporated soft, tendril-like heaters next to the LMPA mesh. The heaters cause the metal to be converted to a liquid at 60 degrees Celsius (140 degrees Fahrenheit), or 10 percent of the melting temperature of aluminum. The elastomer skin keeps the melted metal contained and in place, and then pulls the material back into the original shape, reversing the stretching, giving the composite what the researchers call “reversible plasticity.” After the metal cools, it again contributes to holding the structure’s shape.

“These composites have a metal endoskeleton embedded into a rubber with soft heaters, where the kirigami-inspired cuts define an array of metal beams. These cuts combined with the unique properties of the materials were really important to morph, fix into shape rapidly, then return to the original shape,” Hwang said.

The researchers found that this kirigami-inspired composite design could create complex shapes, from cylinders to balls to the bumpy shape of the bottom of a pepper. Shape change could also be achieved quickly: After impact with a ball, the shape changed and fixed into place in less than 1/10 of a second. Also, if the material broke, it could be healed multiple times by melting and reforming the metal endoskeleton.

One drone for land and air, one for sea

The applications for this technology are only starting to unfold. By combining this material with onboard power, control, and motors, the team created a functional drone that autonomously morphs from a ground to air vehicle. The team also created a small, deployable submarine, using the morphing and returning of the material to retrieve objects from an aquarium by scraping the belly of the sub along the bottom.

“We’re excited about the opportunities this material presents for multifunctional robots. These composites are strong enough to withstand the forces from motors or propulsion systems, yet can readily shape morph, which allows machines to adapt to their environment,” said Barron.

Looking forward, the researchers envision the morphing composites playing a role in the emerging field of soft robotics to create machines that can perform diverse functions, self-heal after being damaged to increase resilience, and spur different ideas in human-machine interfaces and wearable devices.

Here’s link to and a citation for the paper,

Shape morphing mechanical metamaterials through reversible plasticity by Dohgyu Hwang, Edward J. Barron III, A. B. M. Tahidul Haque and Michael D. Bartlett. Science Robotics • 9 Feb 2022 • Vol 7, Issue 63 • DOI: 10.1126/scirobotics.abg2171

This paper is behind a paywall.

Not origami but kirigami-inspired foldable batteries

Origami is not noted for its stretchy qualities, a shortcoming according to a June 16, 2015 news item on Azonano,

Origami, the centuries-old Japanese paper-folding art, has inspired recent designs for flexible energy-storage technology. But energy-storage device architecture based on origami patterns has so far been able to yield batteries that can change only from simple folded to unfolded positions. They can flex, but not actually stretch.

Now an Arizona State University [ASU] research team has overcome the limitation by using a variation of origami, called kirigami, as a design template for batteries that can be stretched to more than 150 percent of their original size and still maintain full functionality.

A June 15, 2015 ASU news release, which originated the news item, provides a few more details about the kirigami-influenced batteries (Note: A link has been removed),

A paper published on June 11 [2015] in the research journal Scientific Reports describes how the team developed kirigami-based lithium-ion batteries using a combination of folds and cuts to create patterns that enable a significant increase in stretchability.

The kirigami-based prototype battery was sewn into an elastic wristband that was attached to a smart watch. The battery fully powered the watch and its functions – including playing video – as the band was being stretched.

“This type of battery could potentially be used to replace the bulky and rigid batteries that are limiting the development of compact wearable electronic devices,” Jiang said.

Such stretchable batteries could even be integrated into fabrics – including those used for clothing, he said.

The researchers have provided a video demonstrating the kirigami-inspired battery in action,

Here’s a link to and a citation for the paper,

Kirigami-based stretchable lithium-ion batteries by Zeming Song, Xu Wang, Cheng Lv, Yonghao An, Mengbing Liang, Teng Ma, David He, Ying-Jie Zheng, Shi-Qing Huang, Hongyu Yu & Hanqing Jiang. Scientific Reports 5, Article number: 10988 doi:10.1038/srep10988 Published 11 June 2015

This is an open access paper.

According to the ASU news release, the team published a previous paper on origami-inspired batteries and some of the problems associated with them (Note: Links have been removed),

An earlier paper in the research journal Nature Communications by Jiang and some of his research team members and other colleagues provides an in-depth look at progress and obstacles in the development of origami-based lithium-ion batteries.

The paper explains technical challenges in flexible-battery development that Jiang says his team’s kirigami-based devices are helping to solve.

Read more about the team’s recent progress and the potential applications of stretchable batteries in Popular Mechanics, the Christian Science Monitor, Yahoo News and the Daily Mail.

Here’s a link to and a citation for the team’s earlier paper,

Origami lithium-ion batteries by Zeming Song, Teng Ma,    Rui Tang, Qian Cheng, Xu Wang, Deepakshyam Krishnaraju, Rahul Panat, Candace K. Chan, Hongyu Yu, & Hanqing Jiang. Nature Communications 5, Article number: 3140 doi:10.1038/ncomms4140 Published 28 January 2014

This paper is behind a paywall but there is a free preview available via ReadCube Access.

On a related note, Dexter Johnson has written up Binghamton University research into paper-based origami batteries powered by the respiration of bacteria in a June 16, 2015 posting on his Nanoclast blog.

Buildable, bendable, and biological; a kirigami-based project at Cornell University

A May 18, 2013 news item on Azonano highlights a new project at Cornell University,

Cornell researchers Jenny Sabin, assistant professor of architecture, and Dan Luo, professor of biological and environmental engineering, are among the lead investigators on a new research project to produce “buildable, bendable and biological materials” for a wide range of applications.

The project is intended to bring new ideas, motifs, portability and design to the formation of intricate chemical, biological and architectural materials.

Based on Kirigami (from the Japanese word kiru, “to cut”), the project “offers a previously unattainable level of design, dynamics and deployability” to self-folding and unfolding materials from the molecular scale to the architectural level, according to the researchers.

The May 16, 2013 Cornell University news release by Daniel Aloi, which originated the news item, describes the project’s intent,

The project is intended to illuminate new principles of architecture, materials synthesis and biological structures, and advance several technologies – including meta-materials, sensors, stealth aircraft and adaptive and sustainable buildings. A complementary goal is to generate public interest through an enhanced impact on science, art and engineering.

“Like the opening and closing of flowers, satellites and even greeting cards, our research will offer a rich and diverse set of intricate surprises, problems and challenges for students at all levels, and broaden their interest and awareness of emerging science and engineering,” according to the project proposal, “Cutting and Pasting: Kirigami in Architecture, Technology and Science” (KATS).

The Emerging Frontiers in Research Innovation grant from the NSF is in the research category of Origami Design for Integration of Self-assembling Systems for Engineering Innovation.

I wish they had a few sample illustrations of how this project might look as a macroscale architectural (or other type of) project even it is a complete fantasy.