양극산화된 알루미늄과 마이크로 인덴테이션을 이용한 3 차원 마이크로-나노 하이브리드 패턴 제작

권종태(Jong Tae Kwon),신홍규(Hong Gue Shin),서영호(Young Ho Seo),김병희(Byeong Hee Kim) 대한기계학회 2007 大韓機械學會論文集A Vol.31 No.12

A simple method for the fabrication of 3D micro-nano hybrid patterns was presented. In conventional fabrication methods of the micro-nano hybrid patterns, micro-patterns were firstly fabricated and then nanopatterns were formatted on the micro-patterns. Moreover, these micro-nano hybrid patterns could be fabricated on the flat substrate. In this paper, we suggested the fabrication method of 3D micro-nano hybrid patterns using micro-indentation on the anodized aluminum substrate. Since diameter of the hemispherical nano-pattern can be controlled by electrolyte and applied voltage in the anodizing process, we can easily fabricated nano-patterns of diameter of 10㎚ to 300㎚. Nano-patterns were firstly formatted on the aluminum substrate, and then micro-patterns were fabricated by deforming the nano-patterned aluminum substrate. Hemispherical nano-patterns of diameter of 150㎚ were fabricated by anodizing process, and then micro-pyramid patterns of the side-length of 50㎛ were formatted on the nano-patterns using microindentation. Finally we successfully replicated 3D micro-nano hybrid patterns by hot-embossing process. 3D micro-nano hybrid patterns can be applied to nano-photonic device and nano-biochip application.

Size effects of micro-pattern on lithium metal surface on the electrochemical performance of lithium metal secondary batteries

Park, Joonam,Kim, Dohwan,Jin, Dahee,Phatak, Charudatta,Cho, Kuk Young,Lee, Young-Gi,Hong, Seungbum,Ryou, Myung-Hyun,Lee, Yong Min Elsevier 2018 Journal of Power Sources Vol.408 No.-

<P><B>Abstract</B></P> <P>Two micro-patterns of different sizes (50 and 80 μm) are designed to have equivalent capacities of 1.06 and 2.44 mAh cm<SUP>−2</SUP> by building a computational battery model. After preparing two stamps each possessing a micro-pattern design, the corresponding pattern is properly imprinted on the surface of 100 μm lithium metal, which is confirmed by scanning electron microscopy. When both micro-patterned lithium metals are electrochemically reduced and oxidized up to 1 mAh cm<SUP>−2</SUP> in Li/Li symmetric cells at 1 or 2 mA cm<SUP>−2</SUP>, the 80 μm-patterned lithium shows a more stabilized lower overpotential during long-term cycling than the 50 μm-patterned and bare lithium, probably due to the lithium anchoring effect and a larger empty volume in the patterns. Additionally, an overflow of lithium deposits is easily observed in the 50 μm-patterned lithium metal, while the 80 μm-patterned lithium metal holds most of the lithium deposits within the patterns. When both micro-patterned lithium metals are assembled to full cells with a LiNi<SUB>0·6</SUB>Co<SUB>0·2</SUB>Mn<SUB>0·2</SUB>O<SUB>2</SUB> cathode of 2 mAh cm<SUP>−2</SUP>, the 80 μm-patterned lithium metal shows much better electrochemical performances with stable plating/stripping behavior within the patterns.</P> <P><B>Highlights</B></P> <P> <UL> <LI> New micro-pattern computationally designed to increase lithium deposition. </LI> <LI> The new pattern on lithium metal lowers overpotential during galvanostatic cycling. </LI> <LI> Cycle life is greatly improved for 200 cycles at high current density. </LI> <LI> The micro-pattern design suppresses undesirable lithium plating and stripping. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Development of Composite Micro-Patterns on Polymer Film using Repetitive Ultrasonic Imprinting

이현중,박근 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.1 No.4

Ultrasonic imprinting is a novel process in which micro-patterns can be replicated on thermoplastic polymer with short processing time and low energy consumption. Ultrasonic imprinting uses ultrasonic vibration energy to soften thermoplastic polymer, and to replicate micro-patterns on the softened polymer surface from a patterned horn or mold. In this study, a new patterning method based on ultrasonic imprinting is proposed to develop composite micro-patterns using a simply-patterned mold. The proposed patterning technology uses repetitive ultrasonic imprinting in which a patterned replica is imprinted repeatedly on a rotated position. To implement this process for the development of composite micro-patterns, two-step repetitive imprinting with 90o rotation was performed using a prism-patterned mold, from which pyramid patterns can be developed. This repetitive imprinting was then further applied to fabricate composite micro-patterns that contain prism and pyramid micropatterns on a single polymer film.

A Study on Manufacturing Method of Nano-Micro Hybrid Pattern Using Indentation Machining Method and AAO Process

김한희(Han-Hee Kim),전은채(Eun-chae Jeon),최대희(Dae-Hee Choi),장웅기(Woong-Ki Jang),박용민(Yong-Min Park),제태진(Tae-Jin Je),최두선(Doo-Sun Choi),김병희(Byeong-Hee Kim),서영호(Young-Ho Seo) Korean Society for Precision Engineering 2015 한국정밀공학회지 Vol.32 No.1

Micro/nano patterns for optical concentration and diffusion have been studied in the various fields such as displays, optics, and sensors. Conventional micro patterns were continuous and linear shapes due to using linear-type light sources, however, recently non-continuous patterns have been applied as point sources are used for dot-type light sources such as LEDs and OLEDs. In this study, a hybrid machining technology combining an indentation machining method and an AAO process was developed for manufacturing the non-continuous micro patterns having nano patterns. First, mirror-like surfaces (R<SUB>a</SUB><20nm) of pure Aluminum substrates were obtained by optimizing cutting conditions. Then, The letter of ‘K’ consisting of the arrays of the micro patterns was manufactured by the indentation machining method which has a similar principle to indentation hardness testing. Finally, nano patterns were machined by AAO process on the micro patterns. Conclusively, a specific letter having nano-micro hybrid patterns was manufactured in this study.

Thermal Reflow 공정 적용 Micro Pattern 형상 변화를 통한 광 향상 구조층 연구

성민호,차지민,문성철,유시홍,이성의,Seong, Min-Ho,Cha, Ji-Min,Moon, Seong-Cheol,Ryung, Si-Hong,Lee, Seong Eui 한국전기전자재료학회 2015 전기전자재료학회논문지 Vol.28 No.5

In this study, the change of optical characteristics was studied according to the micro optical pattern provided by photo lithography followed by thermal reflow process. The shape and luminance variation with micro pattern was evaluated by SEM and spectrometers. Also, we analyzed the luminance characteristics using the 3D-optical simulation (Optis works) program. As a result, we found that the radius of curvature(R) in micro pattern is decreased up to 77%($150^{\circ}C$) compared to the radius of curvature at the condition $100^{\circ}C$, which is caused by efficient reflow of organic material without chemical changes. The highest enhancement of brightness with optimum micro pattern was obtained at the condition of $120^{\circ}C$ reflow process. The brightness gain with optical micro patterns is more than 15% at the condition of R=16.95 um, ${\Theta}=77.14^{\circ}$ compared to original optical source. The results of light simulation with various radius of curvature and side angle of pattern shows the similar result of experiment evaluation of light behavior on optical micro patterns. It is regarded that the more effect on light enhancement was contributed by side angle which is effective factor on light reflection, rather than the curvature of micro-patterns.

펨토초 레이저와 양극산화공정을 이용한 3차원 마이크로-나노하이브리드 패턴 제작

신홍규,권종태,서영호,김병희,정세채 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-

We developed a simple and cost-effective method of fabrication 3D micro-nano hybrid patterns. In the conventional fabrication methods of the micro-nano hybrid patterns, micro-patterns are fabricated firstly on a substrate, and then nano-patterns are formed on the micro-patterns using e-beam, hologram and nano-probe lithography. However, this methods were limited only to 2 dimensional patterns. In order to improve this dimensional limitation and process time, femtosecond laser and AAO process were used. Femtosecond laser with ultra-fast pulse speed and low thermal damage can be modified effectively a metal surface into another material. Also, AAO process can be easily fabricated nano patterns on Al surface. In this study, using the femtosecond laser as a tool of surface modification of Al thin film, several miro patterns with an amorphous layer on the Al thin film were fabricated with respect to laser intensity and scanning speed. Sequently, micro-nano hybrid patterns were fabricated by using a simple AAO process. Finally, we verified the validity of micro-nano hybrid patterns through SEM and EDS.

Optimization of Intense Pulsed Light Sintering Considering Dimensions of Printed Cu Nano/Micro-paste Patterns for Printed Electronics

Yong-Rae Jang,Chung-Hyeon Ryu,Yeon-Taek Hwang,김학성 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.2

An intense pulsed light (IPL) was irradiated for the sintering of screen-printed copper (Cu) nano/micro-paste patterns on a polyimide substrate. The pattern widths and intervals affect the sintering behavior owing to the opto-thermal relationship during IPL irradiation. The temperature histories of the patterns during the IPL sintering process were predicted using a selfdeveloped heat transfer simulation program. By comparing the experimental and simulation results, the tendency according to the size of the Cu pattern was confirmed. At the same IPL irradiation energy, the wider the pattern and the narrower the interval between the patterns, the higher the heat generated. To demonstrate the tendency, in situ resistance monitoring of the Cu patterns was conducted and their microscopic structures were investigated using a scanning electron microscope. Through the tendency of IPL sintering according to the widths and intervals of the Cu pattern, guidelines of IPL sintering process for electrodes with multi-size pattern were suggested: A dummy pattern was added between the existing digitizer patterns to achieve uniform sintering in all regions. When IPL sintering was conducted with the dummy patterns, the uniformly sintered line resistance could be obtained in entire areas of the digitizer pattern.

Micro-patterned membranes with enzymatic quorum quenching activity to control biofouling in an MBR for wastewater treatment

Lee, Jaewoo,Won, Young-June,Choi, Dong-Chan,Lee, Seonki,Park, Pyung-Kyu,Choo, Kwang-Ho,Oh, Hyun-Suk,Lee, Chung-Hak Elsevier 2019 Journal of membrane science Vol.592 No.-

<P><B>Abstract</B></P> <P>In this study, a patterned quorum quenching (QQ) membrane with anti-biofouling characteristics was prepared <I>via</I> a patterning process of an oxidized multiwall carbon nanotube (o-MWCNT) composite membrane followed by immobilization of QQ enzymes. We verified that the o-MWCNTs with a high specific surface area helped the patterned membrane retain 32% more enzyme compared to the case without the o-MWCNTs. Furthermore, the micro-pattern on the membrane surface increased the effective membrane area (~1.6 times), offsetting the membrane resistance additionally caused by enzyme immobilization. The patterned QQ membrane kept the relative activity at above 40% of the initial activity for 39 days due to the cross-linking. It was also confirmed in a flow cell test that the patterned QQ membrane had much more control over biofilm formation by effectively disrupting quorum sensing compared to the patterned membrane. Due to the combined effect of the QQ activity and the pattern effect (<I>e.g.</I>, low permeation drag), the patterned QQ membrane (2.2 times) significantly lengthened the time between chemical cleanings compared to the non-patterned membrane. The combined effect also reduced the specific filtration energy consumption of the patterned QQ membrane to less than half of that of the non-patterned membrane as the two membranes were used to produce the same amount of the treated water during the same period. We expect that the patterned QQ membrane will open and facilitate interdisciplinary research combining patterned membranes with technologies in other areas to improve the antifouling properties of patterned membranes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Interdisciplinary research was conducted to prepare the patterned QQ membrane. </LI> <LI> The patterned QQ membrane effectively suppressed the biofilm formation by QQ effect. </LI> <LI> The micro-pattern offset membrane resistance caused by enzyme immobilization. </LI> <LI> The patterned QQ membrane remarkably prolonged the time between chemical cleanings. </LI> <LI> The patterned QQ membrane consumed significantly less specific filtration energy. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

A study on magnetic abrasive deburring of dual micro pattern

Dong-Hyun Jin,Jae-SeobKwak 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.12

Studies on dual micro pattern are not established because of difficulty of its fabrication and deburring technology. In this investigation, a dual micro pattern which consists of a net pattern and a lenticular pattern was fabricated on a cylindrical workpiece by turning process. Magnetic abrasive deburring (MAD) was proposed as a deburring process in this study. Burr height defined by difference of its height and theoretical pattern height was measured as about 1 μm. It is one of the non-traditional machining methods utilizing flexible tool which consists of ferrous particle and abrasive powder. Hence, the aim of this investigation is to remove generated burr on the dual micro pattern. Burr at the dual micro pattern was removed through MAD, and a prediction equation of machined pattern height was derived. A deburring condition was optimized and verified by experiments. As a result, it was confirmed that dual micro pattern which has high shape accuracy was fabricated using MAD.

Highly transparent micro-patterned protective coatings on polyethylene terephthalate for flexible solar cell applications

Khadem, Mahdi,Park, Tae-Lim,Penkov, Oleksiy V.,Kim, Dae-Eun Elsevier 2018 SOLAR ENERGY -PHOENIX ARIZONA THEN NEW YORK- Vol.171 No.-

<P><B>Abstract</B></P> <P>Degradation of the performance and efficiency of organic solar cells (OSC) due to surface damage, caused by exposure to harsh environments, continues to be a major problem. Therefore, protective coatings must be developed that minimize damage to the outer surface of OSCs, without compromising their transparency and flexibility. For this purpose, ultra-thin, micro-patterned, single/bi-layer coatings comprised of H-free diamond-like-carbon (DLC) and indium tin oxide (ITO) were fabricated. The coatings were deposited onto polyethylene terephthalate (PET) substrates, using magnetron sputtering. The goal of the micro-patterning was to improve the wear resistance of the coatings, while maintaining the high optical transparency of PET. Optical properties, wear resistance, erosion resistance, and flexibility of the coatings were investigated. Furthermore, the performance of a pre-fabricated OSC with and without the proposed protective coating before and after the wear and erosion tests was investigated. The experimental results demonstrated that the wear resistance and transparency (of the single layer micro-patterned DLC coating), was superior to both bi-layer and continuous DLC coatings. The micro-patterned DLC coating caused very little change in transparency (less than 1.7% reduction in the visible spectrum), and reduced the wear rate (mm<SUP>3</SUP>/N·mm) of PET by ∼75%. The erosion resistance of the PET was improved, and its degree of flexibility was unaffected. Overall, the results of OSC performance analysis demonstrated the functionality and potential application of the proposed micro-patterned protective coating for flexible solar cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Micro-patterned functional protective coating was fabricated onto PET. </LI> <LI> Magnetron sputtering deposition technique was used. </LI> <LI> Transparency, wear and erosion resistance, and flexibility were assessed. </LI> <LI> Using micro-patterning, PET transparency and flexibility remained unaffected. </LI> <LI> The functional protective coating can improve the durability of PET-based OSCs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>