Mechanical Engineering Professor Bak Moon Soo‧Professor Park SungSu's research team, Develops Fast and Easy Disinfection

Mechanical Engineering Professor Bak Moon Soo‧Professor Park SungSu's research team, Develops Fast and Easy Disinfection of Coronavirus-contaminated Face Masks Using Ozone Gas - Instant sterilization of coronavirus in 1 minute without sacrificing mask performance. - Expected immediate use in countries with insufficient masks and medical sites requiring frequent replacement. DBD: dielectric barrier discharge. Mechanical engineering professors Bak Moon Soo and Park SungSu's research team (Lee JinYeop, Bong Cheolwoo Ph.D.) reported that they have developed a technology that can be utilized in medical field: high concentration of ozone gases produced by plasma generators on masks contaminated with coronavirus can kill the virus in a minute without compromising the masks's performance at all. After the Corona 19 outbreak, the researchers recognized that many countries were suffering from lakc of supply of N95 (Korea KF94) masks equipped with electrostatic filters and that the long-term use of contaminated masks also increased the infection of medical staff. Researchers succeeded in suppressing infection 100% when the surface of coronavirus infected mask was exposed to disinfectant ozone gas for one minute at the level of 120ppm. It is expected to easily prevent mask contamination by not only coronavirus but other viruses and germs at medical sites. The researchers conducted an experiment (five times per minute, 120ppm ozone gas exposure) on KF94 masks, and were verified by two national certification agencies for mask performance that the dust collection efficiency, which is the main performance of the mask, was maintained at 98%. In addition, the electrostatic filter structure of the mask was confirmed to be intact by using a scanning electron microscope. This means that masks can be recycled at least five times. Ozone generators in the market are designed to sterilize space in the form of air purifiers. However, low-concentration ozone gases are unlikely to be effective against high-concentration viruses or bacterial sterilization. On the other hand, the team's treatment method uses low-temperature, upper-pressure plasma to generate 120ppm of high-concentration ozone gas only in the space where the mask is located to conduct sterilization. As ozone is generated for a short period of one minute, the amount is minimal, and the use of a plasma generator in a hood with good air circulation can prevent ozone-induced hazards. In addition, this technology can be easily applied to mask sterilization by domestic companies that produce plasma generators, and is expected to be able to pioneer the market for overseas exports through the process of optimizing ozone gas exposure to masks. This study which conducted coronavirus infection test had the support of the Ministry of Science and ICT Global Frontier Project (Director Shin Yong-beom of the BioNano Health Guard Research Group) and the BICS (Biomedical Institute for Convergence)-KS (Kangbuk Samsung Hospital) Future Convergence Program The results of this study was pre-published on Friday May 1st on MedRxiv, an internet site that distributes undisclosed manuscripts on health science for rapid dissemination of technology and the present paper is now under review for formal publication. ※ Thesis: Fast and easy disinfection of coronavirus-contaminated face masks using ozone gas produced by a dielectric barrier discharge plasma generator. ※ Thesis source: https://medrxiv.org/cgi/content/short/2020.04.26.20080317v1.

SKKU Joint Research Team Succeeds in Combining Highly Conductive Healable Nanocomposites

SKKU Joint Research Team Succeeds in CombiningHighly Conductive Healable Nanocomposites - The team developed a highly conductivenanocomposite that can be healed even after being deformed and damaged. - The research results are expected to be utilized to improve how damaged electrical circuits are repaired. Prof. Seunghyun Baik’s research team in the School of Mechanical Engineering stated that highly conductive healable nanocomposites were developed with Prof. Seunghyun Baik’s and Prof. Hyungpil Moon’s research teams. Even after repeatedly breaking and recovering more than 1,000 times, the conductivity of the new material can be restored. Researchers Daewoo Suh (Ph.D.) and K. P. Faseela contributed equally as co-first authors. Highly conductive materials that can recover after being deformed and damaged have recently been in the spotlight. This technology is the key to future electric and electronic devices such as artificial skin, IoT, and bioelectronic devices. However, there was a technical limitation that the conductivity of the material could not be fully restored to its original condition when the material had mechanical and electrical damage. The research team succeeded in synthesizing the densely and uniformly distributed silver nanosatellite particle network by chemically etching microscale silver flakes during the composite material mixing process. The conductive network was formed through electronic tunneling without a direct connection between the particles. The network not only reached high electrical conductivity, but also recovered its original structure, even though it had been broken. Even after breaking and healing 1,000 times the electrical conductivity was perfectly restored. The changes in mechanical characteristics were theoretically calculated and the conductivity was maintained stably even when submerged or exposed to air for a long period. The new developed highly conductive healable nanocomposites are putty or playdough-like and are moldable and healable after being damaged. Therefore, this discovery is expected to be applied to the restoration of damaged electrical parts and circuits by using robots in disaster situations or extreme environments where people are restricted from entering. This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2020R1A2C3003199 and NRF-2017R1A2A1A17069289). The results were published on May 7th (Thursday) in Nature Communications, a world-renowned science and technology journal. ※ The title of paper: Electron Tunneling of Hierarchically Structured Silver Nanosatellite Particles for Highly Conductive Healable Nanocomposites Author information: Daewoo Suh (First author), K. P. Faseela (Co-first author), Wonjoon Kim, Chanyong Park, Jang Gyun Lim, Sungwon Seo, Moon Ki Kim, Hyungpil Moon & Seunghyun Baik (Corresponding authors) Journal where the paper is published: Nature Communications https://doi.org/10.1038/s41467-020-15709-8.

Prof. Kim's team Revealed the Carrier-Ion Storage Mechanisms of Electrode Materials in Large Capacity Low Cost Carbon Ba

A research team led by Professor Jaehoon Kim, Department of Mechanical Engineering, Revealed the Carrier-Ion Storage Mechanisms of Electrode Materials in Large Capacity Low Cost Carbon Batteries -Revealed the ionstorage mechanisms of lithium, sodium, and potassium in hard carbon cathodematerials -Selected as coverarticle of Advanced Energy Materials, a world-renowned journal A research team led by Professor Jaehoon Kim, Department of Mechanical Engineering, College of Engineering, Sungkyunkwan University, conducted joint research with a research team led by Professor Sang Kyu Kwak, Ulsan National Institute of Science and Technology. The co-first authors of the research article are researchers Stevanus Alvin and Handi Setiadi Cahyadi. The joint research team revealed the ion storage mechanisms of lithium, sodium, and potassium in hard carbon, which is the most promising anode material that can be used by mid-large size batteries to store energy. The research presented a new path towards developing safe and high-capacity materials. In order to continuously utilize renewable energy sources that do not have stabilized electric power output, such as solar and wind power, it is essential to develop a medium-large size energy storage system that can store renewable electricity and use it when necessary. However, with lithium-ion batteries, it is difficult to develop energy storage systems due to their instability and high prices. Therefore, batteries that store the very abundant and low-priced elements of sodium and potassium in hard carbon are currently in the spotlight, but the ion storage mechanisms had not been established, making it hard to develop high-capacity batteries. The research team synthesized hard carbon prepared by the carbonization of lignin and conducted a systematic study on the changes in the physicochemical properties of hard carbon that change during the charging and discharging of lithium, sodium, and potassium. Furthermore, using the density functional theory, two facts were revealed: 1. The graphene layers were expanded during the sodium and potassium insertion into hard carbon, and 2. There is a larger capacity in sodium and potassium than lithium because there was no expansion. This study is expected to provide ways to improve safe and large capacity medium-large sized power storage batteries and play an important role in the development of new and renewable energy power storage systems. Researcher Handi Setiadi Cahyadi said, “Through this research, the ion storage mechanism in hard carbon, which has been a topic of debate, has been made clear, so now low cost anode materials can be developed to facilitate the creation of mid-large sized power storage.” This research was supported by the Technology Development Program to Solve Climate Changes of the National Research Foundation (NRF) funded by the Ministry of Science, ICT & Future Planning (2017M1A2A2087635). Additional support from the Waste‐to‐Energy Technology Development Program of the Korea Environmental Industry & Technology Institute with financial resources provided by the Ministry of Environment, Republic of Korea (No. 2018001580001) was also appreciated. The research article was published in Advanced Energy Materials, a world-renowned journal in the field of materials science, on April 15th (Wed). Also, it was selected as the cover article of the journal on May 26th (Tue). ※ Original Article: Intercalation Mechanisms: Revealing the Intercalation Mechanisms of Lithium, Sodium, and Potassium in Hard Carbon ※ Source: https://onlinelibrary.wiley.com/doi/abs/10.1002/aenm.202000283 The K- ions hadthe largest ionic radius and revealed the largest edge expansion, making successiveK-ions easily penetrate deeper into hard carbon vacancies between layers.

Prof. Jinkee Lee Developed a 3D Liquid Transporting Diode Surface Using Nature-inspired Technology

Prof. Jinkee Lee Developed a 3D Liquid Transporting Diode Surface Using Nature-inspired Technology Sungkyunkwan University (President Dong Ryeol Shin) announces that Prof. Jinkee Lee in School of Mechanical Engineering & Institute of Quantum Biophysics has developed a 3D liquid transporting diode surface using nature-inspired technology (first author Dr. MinKi Lee). This liquid transporting system has advantages for easy fabrication, cost-effectiveness, high scalability and shows the world's highest performance with novel 3D structure. When a liquid droplet is dispensed on the surface, the liquid transports uni-directionally by the passive capillary control from the structures of the liquid diode. Up to now, diode surfaces have been manufactured using lithography processes or 3D printer, which have drawbacks of limited size with complicated manufacturing processes, and also they show low liquid transport performance. Many researchers have been investigating the diode surface but it is quite challenging to increase both the transport performance and the ease of surface manufacturing, simultaneously. Prof. Jinkee Lee developed nature-inspired diode surface, which mimics the surface from nature such as horned lizard and pitcher plant. The 3D diode surface has a wedge structure consisting of repeating saw-like V-grooves. This surface utilizes the capillary force generated by the 3D topographical shape that pins liquid at one size and makes it flow to the other side. The fabrication of 3D diode surface is easy, fast, cost-effective and scalable because it is processed simply using a laser cutter. Professor Jinkee Lee said, “This 3D water transport diode surface can be applied as an original technology applying to microfluidic diagnostic chips, material synthesis, heat transfer enhancement and even fog collection because of its superior performance and easy fabrication.” This study was supported by the National Research Foundation of Korea (NRF; 2020R1A2C3010568) and the Korea Environment Industry & Technology Institute (KEITI; 2019002790003), and was published online on March 20, 2021 in Advanced Functional Materials (IF=16.836). ※ Title of paper: “Enhanced Liquid Transport on a Highly Scalable, Cost‐Effective, and Flexible 3D Topological Liquid Capillary Diode”