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Eco-Friendly Micro-Supercapacitors Using Fallen Leaves
Green micro-supercapacitors on a single leaf could easily be applied in wearable electronics, smart houses, and IoTs
A KAIST research team has developed graphene-inorganic-hybrid micro-supercapacitors made of fallen leaves using femtosecond laser direct writing. The rapid development of wearable electronics requires breakthrough innovations in flexible energy storage devices in which micro-supercapacitors have drawn a great deal of interest due to their high power density, long lifetimes, and short charging times. Recently, there has been an enormous increase in waste batteries owing to the growing demand and the shortened replacement cycle in consumer electronics. The safety and environmental issues involved in the collection, recycling, and processing of such waste batteries are creating a number of challenges.
Forests cover about 30 percent of the Earth’s surface and produce a huge amount of fallen leaves. This naturally occurring biomass comes in large quantities and is completely biodegradable, which makes it an attractive sustainable resource. Nevertheless, if the fallen leaves are left neglected instead of being used efficiently, they can contribute to fire hazards, air pollution, and global warming.
To solve both problems at once, a research team led by Professor Young-Jin Kim from the Department of Mechanical Engineering and Dr. Hana Yoon from the Korea Institute of Energy Research developed a novel technology that can create 3D porous graphene microelectrodes with high electrical conductivity by irradiating femtosecond laser pulses on the leaves in ambient air. This one-step fabrication does not require any additional materials or pre-treatment.
They showed that this technique could quickly and easily produce porous graphene electrodes at a low price, and demonstrated potential applications by fabricating graphene micro-supercapacitors to power an LED and an electronic watch. These results open up a new possibility for the mass production of flexible and green graphene-based electronic devices.
Professor Young-Jin Kim said, “Leaves create forest biomass that comes in unmanageable quantities, so using them for next-generation energy storage devices makes it possible for us to reuse waste resources, thereby establishing a virtuous cycle.”
This research was published in Advanced Functional Materials last month and was sponsored by the Ministry of Agriculture Food and Rural Affairs, the Korea Forest Service, and the Korea Institute of Energy Research.
-Publication
Truong-Son Dinh Le, Yeong A. Lee, Han Ku Nam, Kyu Yeon Jang, Dongwook Yang, Byunggi Kim, Kanghoon Yim, Seung Woo Kim, Hana Yoon, and Young-jin Kim, “Green Flexible Graphene-Inorganic-Hybrid Micro-Supercapacitors Made of Fallen Leaves Enabled by Ultrafast Laser Pulses," December 05, 2021, Advanced Functional Materials (doi.org/10.1002/adfm.202107768)
-ProfileProfessor Young-Jin KimUltra-Precision Metrology and Manufacturing (UPM2) LaboratoryDepartment of Mechanical EngineeringKAIST
2022.01.27 View 9535 -
KAIST and KNUA to Collaborate on Culture Technology
Distinguished Visiting Scholar Soprano Sumi Jo Accompanied by AI pianist ‘VirtuosoNet’ during the Special Concert at KAIST
KAIST will expand the convergence of arts education and culture technology research in collaboration with the Korea National University of Arts (KNUA), the nation’s top arts university. KAIST President Kwang Hyung Lee signed an MOU with President Daejin Kim of the Korea National University of Art on January 6 at KAIST’s Daejeon campus for collaborations in arts education and research.
KAIST and KNUA will expand educational programs such as student exchanges and co-credit programs. The two universities will team up for cooperation focusing on research centers and academic conferences for the creation of culture technology and convergence arts.
Minister of Culture, Sports, and Tourism Hee Hwang also attended the ceremony. Minister Hwang said that the Ministry will invest 132 billion KRW in R&D for developing metaverse and content technologies. He added that this collaboration will be a very meaningful turning point for creating a new culture combining high-level technologies.
President Kim also expressed his expectations saying, “The collaboration of our two universities will generate a huge synergistic impact for nurturing talents and the creation of convergence arts.
President Lee said that the collaboration with KNUA will take KAIST another step forward as it aims to foster well-rounded talents. “We look forward to proactive collaborative research that will expand the new chapter of convergence arts and future stage performances.”
Right after the signing ceremony, world renowned soprano Sumi Jo, who was named a Distinguished Visiting Scholar, took the KAIST auditorium stage for a special concert. AI pianist ‘VirtuosoNet’, developed by Professor Juhan Nam at the Graduate School of Culture Technology, made its debut at the concert by playing Mozart’s Turkish March arranged by Arcardi Volrodos. VirtuosoNet also accompanied Soprano Jo on one of her songs.
The concert by Sumi Jo and AI pianist VirtuosoNet heralds what KAIST is pursuing for education and research in culture technology. The Graduate School of Culture Technology plans to conduct research on future culture industries combined with technologies for the metaverse. The Sumi Jo Performing Arts Research Center will conduct research on performing technologies together with virtual artists. Head of the Graduate School of Culture Technology Woontack Woo said that KAIST will expand the sphere of the culture industry including tourism in collaboration with KNUA by incorporating technology into arts.
2022.01.10 View 5918 -
KPC4IR Publishes Global Standards Mapping Initiative 2.0
The report highlights South Korea as an early adopter of blockchain in policy and business
The KAIST Policy Center for the 4IR (KPC4IR), one of the nine working groups of the Global Blockchain Business Council (GBBC), published the Global Standards Mapping Initiative (GSMI) 2.0, highlighting Korea as an early adopter of blockchain. The report also offers an overview of how blockchain was adopted through an analysis of policy and business cases of South Korea.
In partnership with 131 institutions, GSMI 2.0 maps, catalogues, and analyzes data from 187 jurisdictions, 479 industry consortia, 38 technical standards, and 389 university courses and degree programs to provide a holistic view of the industry’s global activity.
Among the nine working groups, KAIST is the sole investigator for researching South Korea’s adoption of blockchain for policy and business. It says that in terms of policy and regulations for blockchain as a virtual asset, South Korea amended the Act on Reporting and Using Specific Financial Transaction Information to comply with the Financial Action Task Force’s recommendations.
The report also reviewed South Korea’s blockchain R&D. Seventeen ministries have funded 417 projects to cultivate blockchain inventions since 2015. Significantly, the Ministry of Science and ICT’s Blockchain Convergence Technology Development Program supported 50 projects between 2018 and 2021. Their R&D focused on virtual assets during the initial stage in 2015 and soon shifted its application to various domains, including identification and logistics.
The report noted that the Korea Customs Service was one of the first agencies in the world to introduce blockchain into customs clearance. Through collaborations with the private sector, the Korean government has also created the world’s first blockchain-based vaccination certification services and extended it to a globally integrated decentralized identity system.
Finally, the report states that these South Korean cases highlight three ambiguities in blockchain policies. First, blockchain involves both financial and industrial features. Thus, it needs a new regulatory framework that embraces the two features together.
Second, integrating services on a blockchain platform will bring forth seamless automation of industries across the manufacturing, financial, and public sectors. South Korea, which already has well-proven manufacturing capabilities, is in need of a comprehensive strategy to encompass multiple services on one platform.
Third, the two cases of the government’s adoption of blockchain suggest that innovations in blockchain can be facilitated through effective cooperation among government ministries and agencies regarding particular businesses in the private sector. Consequently, the government’s policy is not simply to invest in virtual assets but also to develop a virtual-physical world woven by blockchain. The new environment demands that South Korea transform its policy stances on blockchain, from specialization to comprehensiveness and cooperation.
Professor So Young Kim who heads the center said, “This report shows the main lessons from South Korea for other countries adopting blockchain. We will continue to work closely with our partners including the World Economic Forum to investigate many other global issues.”
2021.12.21 View 4842 -
A Study Shows Reactive Electrolyte Additives Improve Lithium Metal Battery Performance
Stable electrode-electrolyte interfaces constructed by fluorine- and nitrogen-donating ionic additives provide an opportunity to improve high-performance lithium metal batteries
A research team showed that electrolyte additives increase the lifetime of lithium metal batteries and remarkably improve the performance of fast charging and discharging. Professor Nam-Soon Choi’s team from the Department of Chemical and Biomolecular Engineering at KAIST hierarchized the solid electrolyte interphase to make a dual-layer structure and showed groundbreaking run times for lithium metal batteries.
The team applied two electrolyte additives that have different reduction and adsorption properties to improve the functionality of the dual-layer solid electrolyte interphase. In addition, the team has confirmed that the structural stability of the nickel-rich cathode was achieved through the formation of a thin protective layer on the cathode. This study was reported in Energy Storage Materials.
Securing high-energy-density lithium metal batteries with a long lifespan and fast charging performance is vital for realizing their ubiquitous use as superior power sources for electric vehicles. Lithium metal batteries comprise a lithium metal anode that delivers 10 times higher capacity than the graphite anodes in lithium-ion batteries. Therefore, lithium metal is an indispensable anode material for realizing high-energy rechargeable batteries. However, undesirable reactions among the electrolytes with lithium metal anodes can reduce the power and this remains an impediment to achieving a longer battery lifespan. Previous studies only focused on the formation of the solid electrolyte interphase on the surface of the lithium metal anode.
The team designed a way to create a dual-layer solid electrolyte interphase to resolve the instability of the lithium metal anode by using electrolyte additives, depending on their electron accepting ability and adsorption tendencies. This hierarchical structure of the solid electrolyte interphase on the lithium metal anode has the potential to be further applied to lithium-alloy anodes, lithium storage structures, and anode-free technology to meet market expectations for electrolyte technology.
The batteries with lithium metal anodes and nickel-rich cathodes represented 80.9% of the initial capacity after 600 cycles and achieved a high Coulombic efficiency of 99.94%. These remarkable results contributed to the development of protective dual-layer solid electrolyte interphase technology for lithium metal anodes.
Professor Choi said that the research suggests a new direction for the development of electrolyte additives to regulate the unstable lithium metal anode-electrolyte interface, the biggest hurdle in research on lithium metal batteries.
She added that anode-free secondary battery technology is expected to be a game changer in the secondary battery market and electrolyte additive technology will contribute to the enhancement of anode-free secondary batteries through the stabilization of lithium metal anodes.
This research was funded by the Technology Development Program to Solve Climate Change of the National Research Foundation in Korea funded by the Ministry of Science, ICT & Future Planning and the Technology Innovation Program funded by the Ministry of Trade, Industry & Energy, and Hyundai Motor Company.
- PublicationSaehun Kim, Sung O Park, Min-Young Lee, Jeong-A Lee, Imanuel Kristanto, Tae Kyung Lee, Daeyeon Hwang, Juyoung Kim, Tae-Ung Wi, Hyun-Wook Lee, Sang Kyu Kwak, and NamSoon Choi, “Stable electrode-electrolyte interfaces constructed by fluorine- and nitrogen-donating ionic additives for high-performance lithium metal batteries,” Energy Storage Materials,45, 1-13 (2022), (doi: https://doi.org/10.1016/j.ensm.2021.10.031)
- ProfileProfessor Nam-Soon ChoiEnergy Materials LaboratoryDepartment of Chemical and Biomolecular EngineeringKAIST
2021.12.16 View 7446 -
A Team of Three PhD Candidates Wins the Korea Semiconductor Design Contest
“We felt a sense of responsibility to help the nation advance its semiconductor design technology”
A CMOS (complementary metal-oxide semiconductor)-based “ultra-low noise signal chip” for 6G communications designed by three PhD candidates at the KAIST School of Electrical Engineering won the Presidential Award at the 22nd Korea Semiconductor Design Contest.
The winners are PhD candidates Sun-Eui Park, Yoon-Seo Cho, and Ju-Eun Bang from the Integrated Circuits and System Lab run by Professor Jaehyouk Choi. The contest, which is hosted by the Ministry of Trade, Industry and Energy and the Korea Semiconductors Industry Association, is one of the top national semiconductor design contests for college students.
Park said the team felt a sense of responsibility to help advance semiconductor design technology in Korea when deciding to participate the contest. The team expressed deep gratitude to Professor Choi for guiding their research on 6G communications.
“Our colleagues from other labs and seniors who already graduated helped us a great deal, so we owe them a lot,” explained Park. Cho added that their hard work finally got recognized and that acknowledgement pushes her to move forward with her research. Meanwhile, Bang said she is delighted to see that many people seem to be interested in her research topic.
Research for 6G is attempting to reach 1 tera bps (Tbps), 50 times faster than 5G communications with transmission speeds of up to 20 gigabytes. In general, the wider the communication frequency band, the higher the data transmission speed. Thus, the use of frequency bands above 100 gigahertz is essential for delivering high data transmission speeds for 6G communications.
However, it remains a big challenge to make a precise benchmark signal that can be used as a carrier wave in a high frequency band. Despite the advantages of CMOS’s ultra-small and low-power design, it still has limitations at high frequency bands and its operating frequency. Thus, it was difficult to achieve a frequency band above 100 gigahertz.
To overcome these challenges, the three students introduced ultra-low noise signal generation technology that can support high-order modulation technologies. This technology is expected to contribute to increasing the price competitiveness and density of 6G communication chips that will be used in the future.
5G just got started in 2020 and still has long way to go for full commercialization. Nevertheless, many researchers have started preparing for 6G technology, targeting 2030 since a new cellular communication appears in every other decade.
Professor Choi said, “Generating ultra-high frequency signals in bands above 100 GHz with highly accurate timing is one of the key technologies for implementing 6G communication hardware. Our research is significant for the development of the world’s first semiconductor chip that will use the CMOS process to achieve noise performance of less than 80fs in a frequency band above 100 GHz.”
The team members plan to work as circuit designers in Korean semiconductor companies after graduation. “We will continue to research the development of signal generators on the topic of award-winning 6G. We would like to continue our research on high-speed circuit designs such as ultra-fast analog-to-digital converters,” Park added.
2021.11.30 View 6889 -
Scientists Develop Wireless Networks that Allow Brain Circuits to Be Controlled Remotely through the Internet
Wireless implantable devices and IoT could manipulate the brains of animals from anywhere around the world due to their minimalistic hardware, low setup cost, ease of use, and customizable versatility
A new study shows that researchers can remotely control the brain circuits of numerous animals simultaneously and independently through the internet. The scientists believe this newly developed technology can speed up brain research and various neuroscience studies to uncover basic brain functions as well as the underpinnings of various neuropsychiatric and neurological disorders.
A multidisciplinary team of researchers at KAIST, Washington University in St. Louis, and the University of Colorado, Boulder, created a wireless ecosystem with its own wireless implantable devices and Internet of Things (IoT) infrastructure to enable high-throughput neuroscience experiments over the internet. This innovative technology could enable scientists to manipulate the brains of animals from anywhere around the world. The study was published in the journal Nature Biomedical Engineering on November 25
“This novel technology is highly versatile and adaptive. It can remotely control numerous neural implants and laboratory tools in real-time or in a scheduled way without direct human interactions,” said Professor Jae-Woong Jeong of the School of Electrical Engineering at KAIST and a senior author of the study. “These wireless neural devices and equipment integrated with IoT technology have enormous potential for science and medicine.”
The wireless ecosystem only requires a mini-computer that can be purchased for under $45, which connects to the internet and communicates with wireless multifunctional brain probes or other types of conventional laboratory equipment using IoT control modules. By optimally integrating the versatility and modular construction of both unique IoT hardware and software within a single ecosystem, this wireless technology offers new applications that have not been demonstrated before by a single standalone technology. This includes, but is not limited to minimalistic hardware, global remote access, selective and scheduled experiments, customizable automation, and high-throughput scalability.
“As long as researchers have internet access, they are able to trigger, customize, stop, validate, and store the outcomes of large experiments at any time and from anywhere in the world. They can remotely perform large-scale neuroscience experiments in animals deployed in multiple countries,” said one of the lead authors, Dr. Raza Qazi, a researcher with KAIST and the University of Colorado, Boulder. “The low cost of this system allows it to be easily adopted and can further fuel innovation across many laboratories,” Dr. Qazi added.
One of the significant advantages of this IoT neurotechnology is its ability to be mass deployed across the globe due to its minimalistic hardware, low setup cost, ease of use, and customizable versatility. Scientists across the world can quickly implement this technology within their existing laboratories with minimal budget concerns to achieve globally remote access, scalable experimental automation, or both, thus potentially reducing the time needed to unravel various neuroscientific challenges such as those associated with intractable neurological conditions.
Another senior author on the study, Professor Jordan McCall from the Department of Anesthesiology and Center for Clinical Pharmacology at Washington University in St. Louis, said this technology has the potential to change how basic neuroscience studies are performed. “One of the biggest limitations when trying to understand how the mammalian brain works is that we have to study these functions in unnatural conditions. This technology brings us one step closer to performing important studies without direct human interaction with the study subjects.”
The ability to remotely schedule experiments moves toward automating these types of experiments. Dr. Kyle Parker, an instructor at Washington University in St. Louis and another lead author on the study added, “This experimental automation can potentially help us reduce the number of animals used in biomedical research by reducing the variability introduced by various experimenters. This is especially important given our moral imperative to seek research designs that enable this reduction.”
The researchers believe this wireless technology may open new opportunities for many applications including brain research, pharmaceuticals, and telemedicine to treat diseases in the brain and other organs remotely. This remote automation technology could become even more valuable when many labs need to shut down, such as during the height of the COVID-19 pandemic.
This work was supported by grants from the KAIST Global Singularity Research Program, the National Research Foundation of Korea, the United States National Institute of Health, and Oak Ridge Associated Universities.
-PublicationRaza Qazi, Kyle Parker, Choong Yeon Kim, Jordan McCall, Jae-Woong Jeong et al. “Scalable and modular wireless-network infrastructure for large-scale behavioral neuroscience,” Nature Biomedical Engineering, November 25 2021 (doi.org/10.1038/s41551-021-00814-w)
-ProfileProfessor Jae-Woong JeongBio-Integrated Electronics and Systems LabSchool of Electrical EngineeringKAIST
2021.11.29 View 11877 -
Renault 5 EV and Canoo’s Pickup Truck Win the 2021 FMOTY Awards
KAIST Future Mobility of the Year Awards recognize the most innovative concept cars of the year
The Renault 5 EV from France and a pickup truck from the US startup Canoo won the 2021 Future Mobility of the Year Awards (FMOTY) hosted by the Cho Chun Shik Graduate School of Green Transportation at KAIST. The awards ceremony was held at Renault Samsung Motors in Seoul on November 25.
KAIST began the FMOTY in 2019 to advance future car technology and stimulate growth in the industry. The award recognizes the most innovative ideas for making the most futuristic concept car and improving the technological and social value of the industry.
The awards ceremony was attended by KAIST President Kwang Hyung Lee, the dean of the Cho Chun Shik Graduate School of Green Transportation In Gwun Jang, CEO of Renault Samsung Motors Dominique Signora, and CEO of Canoo Tony Aquila. President Lee said, “The new world order will be impacted by new technology developers who envision the future. Their innovation and creative ideas will open a new world of sustainable future transportation.”
Out of the 46 concept cars revealed at global motor exhibitions between last year and the first quarter of this year, models demonstrating transport technology useful for future society and innovative service were selected in the categories of passenger cars and commercial vehicles.
Sixteen automotive journalists from 11 countries, including the chief editor of Car Magazine in Germany Georg Kacher and editorial director of BBC Top Gear Charlie Turner, participated as judges.
This year’s award for the best concept car for a passenger vehicle went to an electric vehicle, the Renault 5 EV. The compact electric car was highly regarded for its practicality and environmental friendliness. A pickup truck by Canoo, an American EV manufacturing start-up, won the award in the commercial vehicle category. The pickup features an innovative design allowing for a variety of functions topped with a competitive price and it received overwhelming support from the judges.
While Hyundai Motors swept both prizes at the awards last year and demonstrated the potential of Korean concept cars, Canoo’s win in the commercial vehicle section as a young American venture company brought attention to the changing dynamics in the automotive market. This shows that young EV start-ups can compete with existing car companies as the automotive paradigm is shifting from those with internal combustion engines to EVs.
The awards organizers said that the Cho Chun Shik Graduate School of Green Transportation will continue to hold the FMOTY to lead the fast-changing global mobility market. For more information, please visit www.fmoty.org.
2021.11.26 View 5834 -
A Genetic Change for Achieving a Long and Healthy Life
Researchers identified a single amino acid change in the tumor suppressor protein in PTEN that extends healthy periods while maintaining longevity
Living a long, healthy life is everyone’s wish, but it is not an easy one to achieve. Many aging studies are developing strategies to increase health spans, the period of life spent with good health, without chronic diseases and disabilities. Researchers at KAIST presented new insights for improving the health span by just regulating the activity of a protein.
A research group under Professor Seung-Jae V. Lee from the Department of Biological Sciences identified a single amino acid change in the tumor suppressor protein phosphatase and tensin homolog (PTEN) that dramatically extends healthy periods while maintaining longevity. This study highlights the importance of the well-conserved tumor suppressor protein PTEN in health span regulation, which can be targeted to develop therapies for promoting healthy longevity in humans. The research was published in Nature Communications on September 24, 2021.
Insulin and insulin-like growth factor-1 (IGF-1) signaling (IIS) is one of the evolutionarily conserved aging-modulatory pathways present in life forms ranging from tiny roundworms to humans. The proper reduction of IIS leads to longevity in animals but often causes defects in multiple health parameters including impaired motility, reproduction, and growth.
The research team found that a specific amino acid change in the PTEN protein improves health status while retaining the longevity conferred by reduced IIS. They used the roundworm C. elegans, an excellent model animal that has been widely used for aging research, mainly because of its very short normal lifespan of about two to three weeks. The PTEN protein is a phosphatase that removes phosphate from lipids as well as proteins. Interestingly, the newly identified amino acid change delicately recalibrated the IIS by partially maintaining protein phosphatase activity while reducing lipid phosphatase activity.
As a result, the amino acid change in the PTEN protein maintained the activity of the longevity-promoting transcription factor Forkhead Box O (FOXO) protein while restricting the detrimental upregulation of another transcription factor, NRF2, leading to long and healthy life in animals with reduced IIS.
Professor Lee said, “Our study raises the exciting possibility of simultaneously promoting longevity and health in humans by slightly tweaking the activity of one protein, PTEN.”
This work was supported by the MInistry of Science and ICT through the National Research Foundation of Korea.
-Publication:Hae-Eun H. Park, Wooseon Hwang, Seokjin Ham, Eunah Kim, Ozlem Altintas, Sangsoon Park, Heehwa G. Son, Yujin Lee, Dongyeop Lee, Won Do Heo, and Seung-Jae V. Lee. 2021. “A PTEN variant uncouples longevity from impaired fitness in Caenorhabditis elegans with reduced insulin/IGF-1 signaling,” Nature Communications, 12(1), 5631. (https://doi.org/10.1038/s41467-021-25920-w)
-ProfileProfessor Seung-Jae V. LeeMolecular Genetics of Aging LaboratoryDepartment of Biological Sciences KAIST
2021.11.19 View 6931 -
Marien Buissonniere Awarded the 9th Grand Award for Future Strategy
Global healthcare and humanitarian activist honored by the Grand Award for Future Strategy
The Moon Soul Graduate School of Future Strategy awarded the 9th Grand Award for Future Strategy to Marine Buissonniere, an independent advisor and practitioner in the fields of global health and humanitarian action. She currently works as a senior advisor to the Prevent Epidemics team at Resolve to Save Lives. She also co-chairs Doctors Without Borders’ Transformational Investment Capacity.
Buissonniere was recognized for designing and implementing global response strategies in global strife and disaster stricken areas over the 25 years while serving as secretary general of Doctors Without Borders. She has been working with various government agencies around the world including Resolve to Save Lives to respond to the Covid-19 pandemic and preparing global future strategies for the post-pandemic era.
The Grand Award for Future Strategy recognizes individual and organization who have contributed to the nation and humanity through future research and strategies in the fields of science and technology, economy and industry, society and culture, politics and governance, and resources and environment.
The selection committee place particular emphasis on her humanitarian efforts toward North Korea. She was in charge of the task force for resuming the health project in North Korea and facilitated the North Korean program in 2002. She also played a significant role in raising awareness of North Korea’s humanitarian issues in the international community by lecturing at Columbia and Princeton.
Buissonniere said during the awards ceremony held online on November 5, “I am very grateful to receive this award from KAIST, a world’s top-flight university as well as from South Korea related to the Korean Peninsula and North Korea, where I have spent most of my life. What makes this award even more special is it is about the international medical relief activities and system innovations that I’ve devoted my life to over the last 25 years. I am going to continue this journey to help many people in difficult situations. Eventually, I would like to make it possible for those people in need to make their own future by themselves.”
2021.11.11 View 5259 -
Nanoscale Self-Assembling Salt-Crystal ‘Origami’ Balls Envelop Liquids
Mechanical engineers have devised a ‘crystal capillary origami’ technique where salt crystals spontaneously encapsulate liquid droplets
Researchers have developed a technique whereby they can spontaneously encapsulate microscopic droplets of water and oil emulsion in a tiny sphere made of salt crystals—sort of like a minute, self-constructing origami soccer ball filled with liquid. The process, which they are calling ‘crystal capillary origami,’ could be used in a range of fields from more precise drug delivery to nanoscale medical devices.The technique is described in a paper appearing in the journal Nanoscale on September 21.
Capillary action, or ‘capillarity,’ will be familiar to most people as the way that water or other liquids can move up narrow tubes or other porous materials seemingly in defiance of gravity (for example within the vascular systems of plants, or even more simply, the drawing up of paint between the hairs of a paintbrush). This effect is due to the forces of cohesion (the tendency of a liquid’s molecules to stick together), which results in surface tension, and adhesion (their tendency to stick to the surface of other substances). The strength of the capillarity depends on the chemistry of the liquid, the chemistry of the porous material, and on the other forces acting on them both. For example, a liquid with lower surface tension than water would not be able to hold up a water strider insect.
Less well known is a related phenomenon, elasto-capillarity, that takes advantage of the relationship between capillarity and the elasticity of a very tiny flat sheet of a solid material. In certain circumstances, the capillary forces can overcome the elastic bending resistance of the sheet.
This relationship can be exploited to create ‘capillary origami,’ or three-dimensional structures. When a liquid droplet is placed on the flat sheet, the latter can spontaneously encapsulate the former due to surface tension. Capillary origami can take on other forms including wrinkling, buckling, or self-folding into other shapes. The specific geometrical shape that the 3D capillary origami structure ends up taking is determined by both the chemistry of the flat sheet and that of the liquid, and by carefully designing the shape and size of the sheet.
There is one big problem with these small devices, however. “These conventional self-assembled origami structures cannot be completely spherical and will always have discontinuous boundaries, or what you might call ‘edges,’ as a result of the original two-dimensional shape of the sheet,” said Kwangseok Park, a lead researcher on the project. He added, “These edges could turn out to be future defects with the potential for failure in the face of increased stress.” Non-spherical particles are also known to be more disadvantageous than spherical particles in terms of cellular uptake.
Professor Hyoungsoo Kim from the Department of Mechanical Engineering explained, “This is why researchers have long been on the hunt for substances that could produce a fully spherical capillary origami structure.”
The authors of the study have demonstrated such an origami sphere for the first time. They showed how instead of a flat sheet, the growth of salt-crystals can perform capillary origami action in a similar manner. What they call ‘crystal capillary origami’ spontaneously constructs a smooth spherical shell capsule from these same surface tension effects, but now the spontaneous encapsulation of a liquid is determined by the elasto-capillary conditions of growing crystals.
Here, the term ‘salt’ refers to a compound of one positively charged ion and another negatively charged. Table salt, or sodium chloride, is just one example of a salt. The researchers used four other salts: calcium propionate, sodium salicylate, calcium nitrate tetrahydrate, and sodium bicarbonate to envelop a water-oil emulsion. Normally, a salt such as sodium chloride has a cubical crystal structure, but these four salts form plate-like structures as crystallites or ‘grains’ (the microscopic shape that forms when a crystal first starts to grow) instead. These plates then self-assemble into perfect spheres.
Using scanning electron microscopy and X-ray diffraction analysis, they investigated the mechanism of such formation and concluded that it was ‘Laplace pressure’ that drives the crystallite plates to cover the emulsion surface. Laplace pressure describes the pressure difference between the interior and exterior of a curved surface caused by the surface tension at the interface between the two substances, in this case between the salt water and the oil.
The researchers hope that these self-assembling nanostructures can be used for encapsulation applications in a range of sectors, from the food industry and cosmetics to drug delivery and even tiny medical devices.
-Publication
Kwangseok Park, Hyoungsoo Kim “Crystal capillary origami capsule with self-assembled nanostructure,” Nanoscale, 13(35), 14656-14665 (DOI: 10.1039/d1nr02456f)
-Profile
Professor Hyoungsoo Kim
Fluid and Interface Laboratory
http://fil.kaist.ac.kr
Department of Mechanical Engineering
KAIST
2021.11.04 View 7447 -
Minister of Justice Meets with KAIST International Community Members
The Office of Immigration Service in Daejeon will dispatch On-Site Immigration Service Team at the campus once a week
Minister of Justice Beom Kye Park met with international students and faculty members on October 29 at the KAIST campus and promised the government’s prompt and flexible revision of the process for acquiring legal residency and Korean citizenship for talents in the fields of science and technology.
During the meeting to discuss immigration difficulties with foreign students, researchers, and faculty at KAIST, many KAIST international students expressed their wishes to continue their research in Korea after graduation and asked for legal support to acquire permanent residence status.
International faculty members including PhD and Master’s candidate and postdoc fellows attended the meeting along with KAIST President Kwang Hyung Lee and Assistant Vice President of the International Office Scott Knowles.
Currently, there are 1,100 international members on campus: 421 undergraduates, 236 Master’s student, 266 PhD candidates, 79 researchers, and 67 faculty members.
President Lee said, “It is prerequisite to nurture the outstanding talents who earned their degrees in Korea for raising our national competitiveness. We would like to ask the government to ease the current system to embrace those excellent talents. That will definitely be necessary for securing new talents as well as for invigorating the domestic industry and R&D sector, which will lead to attracting the next excellent groups of talented students from abroad.”
Minister Park said that the government now needs more inclusive immigration policies granting legal residency and citizenship to the highly talented group. He added that the ministry will make every effort to help our degree holders acquire the relevant legal status to settle down here.
Meanwhile, the Office of Immigration Services in Daejeon set up the ‘On-Site Immigration Service’ at the campus and provided one-on-one consultation services for KAIST international community regarding extension of stays and alien registration affairs.
The On-Site Immigration Service will continue at the campus once a week for convenience of KAIST international community in the very near future.
2021.10.29 View 3933 -
GSI Forum Highlights Global Collaboration Toward a Sustainable Global Economy
The forum stresses global collaboration to make the global value chain more resilient
Speakers at the 5th Global Strategy Institute International Forum on October 28 stressed the importance of global collaboration for rebuilding the global economy and making innovations in national science and technology governance in order to enhance national competitiveness. The forum entitled “Grand Strategic Shift under Global Techno-Geopolitical Paradigm” examined strategies for making the global supply chain more resilient and rebuild the global economy as well as how Korea could advance in the technology race.
Speakers concurred that technology has become an issue of national security. The global supply chain has been disrupted amid the global pandemic and intense conflict between the U.S. and China. Speakers presented a common solution: global collaboration and innovations in science and technology governance.
KAIST President Kwang Hyung Lee said in his opening remarks that the future ‘world map’ may turn out very differently depending on how we prepare and what we envision for the future. He also stressed the importance of technology sovereignty, adding that only those who can create their own new technology independently will be the future leaders.
Prime Minister Boo Kyum Kim and Vice Minister of Science and ICT Hongtaek Yong delivered congratulatory remarks. Keynote speakers included Professor Scott Stern from the MIT Sloan School of Management, Professor Aaron Chatterji from the Fuqua School of Business at Duke University, Professor Sarah Kreps from the Department of Government at Cornell University, SK Group Chairperson Tae-Won Chey, President Woo Il Lee of the Korean Federation of Science and Technology Societies, Professor Young Kwan Yoon at Seoul National University, President Eun Mee Kim of Ewha Womans University, and President Ieehwan Kim of the University of Science and Technology.
During the first session, Professor Chatterji stressed that how to make supply chains resilience will be the key for making long-term strategy with relevant government policy. He said that AI has become a general purpose technology (GPT) and Korea ranked 4th in AI innovation in the world, but how to translate this innovativeness into national strategic leadership will be a new challenge for Korea. He suggested that Korea strengthen its strategic partnerships with allies such as the U.S. and provide opportunities not only for established players but start-ups and entrepreneurs. Meanwhile, Professor Kreps said that industrial policy should also leverage trust and innovations for building technology alliances with a more longer-term approach, without antagonizing certain groups of nations.
Vice President for Planning and Budget Bowon Kim who joined the forum as a discussant pointed out that in this hyper-connected era, nothing can be manufactured in a single company and country without the global supply chain. “In longer-term policy and strategies, we should embrace China as a global economy partner and include all nations around the world.”
Chairman Chey from SK said that the clear role among universities, industry, and the government doesn’t exist any longer. Now, universities are working hard for the commercialization of technology from their labs. Industry is nurturing the talents inept for future industry, and the government is trying to introduce a more private-sector approach. As such, universities, the government, and industry should embrace all-inclusive approaches encompassing global politics and trade to lead on the global stage.
Meanwhile in the second session, all of the speakers stressed innovation in science and technology governance in order to adopt to the new industrial paradigm. They agreed to make prompt innovations and solid collaborative systems among the government ministries to ensure national competitiveness, especially in the field of science and technology.
President Lee from KOFST said Korea should adopt a first mover strategy and the government should adopt a mission-oriented projects and deregulate more. He pointed out that when mandating more autonomy in decision making, scientists and students can make more creative outcomes.
Professor Yoon at SNU stressed the close alliance with the U.S. in the technology race, but suggested that Korea should also seek ways to help minimize the technology gap between advanced and developing countries. Universities should also be allowed more autonomy in running creative curriculum and academic affairs to in order boost the competitiveness of science and technology.
President Kim from Ewha pointed out the role of education as a public good. In some countries, strengthening science and technology can be accomplished with wider educational opportunities in middle and high schools. President Kim also stressed expanding strategic partnerships. She said Korea should expand its alliances and partnerships, not only with the U.S. but with European countries and other niche countries where certain technologies are superior.
President Kim of UST stressed a new science and technology leadership is required to build technology sovereignty and the government should spearhead the deregulations of the government policy.
This GSI forum was co-hosted by two think-tanks at KAIST, the Korea Policy Center for the Fourth Industrial Revolution (KPC4IR) and the Innovation Strategy and Policy Institute (ISPI).
2021.10.28 View 7069