Article
Polymer Science
Yeseong Seo, So Yeong Park, Jaeyong Lee, Jin Kon Kim, Chao Duan, Weihua Li
Summary: The morphology formed in a binary blend of two different copolymers can vary depending on the molecular weights and volume fractions, with cylindrical microdomains forming when there is a significant difference in molecular weights and a lamellar morphology observed when the molecular weights are closer. This study also found interesting inverted cylinders formed in certain conditions, with the stability of these structures attributed to factors such as domain swelling and radial distribution of polymer blocks. Self-consistent field theory (SCFT) was used to verify experimental results.
Article
Polymer Science
Changyeon Lee, Chinedum O. Osuji
Summary: Liquid-crystal polymers combine the characteristics of liquid crystals and polymers, exhibiting intriguing physical phenomena and useful properties. Over the past nearly 50 years, there has been significant expansion in the field, with developments in new chain architectures, new classes of mesogens, and exploration of new properties and applications. Opportunities for LCPs, particularly in nanopatterning and beyond, are emerging with the ability to access small feature sizes and fluidity of the LC mesophase presenting compelling possibilities for orientation control.
Article
Polymer Science
Sanghoon Kim, Wonjun Kang, Chunghwan Jung, Mooseong Kim, Keon-Woo Kim, Myeongcheol Go, Nara Jeon, Junsuk Rho, Jaeup U. Kim, Jin Kon Kim
Summary: We studied the morphology of lamellae-forming polystyrene-block-poly(methyl methacrylate) copolymer (PS-b-PMMA) confined in asymmetric hemisphere nanocavities. Different patterns, including concentric lamellar and WiFi-like nanopatterns, were observed on the top surface of the nanocavities depending on the thickness of the deposited gold layer. The reduction of dislocations of PS and PMMA lamellar microdomains near the center of the nanocavity led to the formation of WiFi-like patterns. The modification of the inner wall of the nanocavity with different polymer brushes also resulted in different nanopatterns, such as WiFi-like and laterally stacked U-shaped patterns.
Article
Nanoscience & Nanotechnology
Jin Yong Shin, Bom Lee, Heo Yeon Lim, Simon Kim, Seong-Jun Jeong
Summary: The proposed TDSA method allows for neutral surface-free vertical orientations of BCP nanopatterns, independent of substrate polarizability, and can generate various morphologies by adjusting trench width and BCP molecular weight. This method has the potential advantage for designing process/device layouts needed for effective manufacturing processes.
Article
Polymer Science
Hiroki Hamamoto, Hideaki Takagi, Isamu Akiba, Katsuhiro Yamamoto
Summary: Anomalous grazing incidence small-angle X-ray scattering (AGISAXS) was used to analyze the dispersion state of brominated homopolymer in PS-PHS/Br-PHS blend thin films. The results showed that Br-PHS segregated to the PS-PHS interface to reduce the interfacial energy.
Article
Polymer Science
Ki Hyun Kim, Mincheol Kim, Junsoo Moon, June Huh, Joona Bang
Summary: In this study, bottlebrush copolymers were designed as neutral additives to block copolymer (BCP) thin films, achieving vertically oriented microdomains through architectural effects. This concept could potentially be extended to various applications requiring polymer films with functional surfaces.
Article
Polymer Science
Mingyang Chen, Yuguo Chen, Yanyan Zhu, Ying Jiang, David Andelman, Xingkun Man
Summary: We investigated the influence of chain flexibility on the self-assembly behavior of symmetric diblock copolymers (BCPs) in thin film confinement. Using worm-like chain (WLC) self-consistent field theory, we studied the stability of parallel and perpendicular orientations of BCP lamellar phases under varying chain flexibilities. The results showed that the stability of perpendicular lamellae increases with chain rigidity, except for the case of rigid chains on rough substrates where the stability decreases. We also demonstrated the effect of substrate roughness on the critical value of substrate preference for the transition from perpendicular-to-parallel lamellar phases.
Article
Polymer Science
Ivan Mikhailov, Frans A. M. Leermakers, Anatoly A. Darinskii, Ekaterina B. Zhulina, Oleg Borisov
Summary: This study develops a theory describing lamellar mesophases in the melt of ABA triblock copolymers with strongly incompatible comblike blocks, using a combination of analytical and numerical approaches. The structural and thermodynamic properties of the lamellae are analyzed as a function of the architectural parameters of the comb-shaped blocks. The study predicts an increase in the shear modulus of the mesophase upon replacing linear ABA triblock copolymers with comblike ones of the same composition, demonstrating the impact of the comblike block parameters on the properties of the mesophase.
Article
Polymer Science
Mariusz Gadzinowski, Maciej Kasprow, Teresa Basinska, Stanislaw Slomkowski, Lukasz Otulakowski, Barbara Trzebicka, Tomasz Makowski
Summary: This paper developed an original method to synthesize Coil-Brush copolymers and verified the hypothesis that the hydrophilicity and micellization of these copolymers can be controlled by the polyglycidol blocks architecture. The behavior of different copolymers in water was compared, and it was found that the brush copolymers had much higher CMC values than the linear copolymers with similar PGL content.
Article
Nanoscience & Nanotechnology
Anette Lofstrand, Reza Jafari Jam, Johannes Svensson, Adam Jonsson, Heera Menon, Daniel Jacobsson, Lars-Erik Wernersson, Ivan Maximov
Summary: Fabricating next generation transistors requires new technological requirements, such as smaller size and higher density structures. This study demonstrates the use of directed self-assembly of block copolymer to fabricate vertical III-V nanowires with small pitch, which is important for realizing dense gate all-around transistors. It is also shown that the orientation of the block copolymer affects the facet configuration of the nanowires and their spacing.
ADVANCED ELECTRONIC MATERIALS
(2022)
Article
Polymer Science
Karthika Madathil, Banafsheh Hekmatnia, Haleh Ardebili, Gila E. Stein
Summary: This study examines the impact of solvent composition and solution-casting process on the structure and properties of a lamellar sulfonated pentablock copolymer (SPC) membrane. The results show that sequential deposition of multiple layers can predict the structure of dry films and processing conditions strongly influence through-plane transport properties. This study provides valuable insights for optimizing critical transport properties.
Article
Polymer Science
Ekaterina B. Zhulina, Ivan V. Mikhailov, Oleg V. Borisov
Summary: In this study, a theory describing the equilibrium morphology and structural properties of solvent-free mesophases of ABA triblock copolymers is developed. The effect of dead zones on the stability of different mesophases is considered by implementing a two-layer model. The predicted domain sizes and interdomain distances are compared to experimental data.
Article
Nanoscience & Nanotechnology
Jiajing Li, Paulina A. Rincon-Delgadillo, Hyo Seon Suh, Geert Mannaert, Paul F. Nealey
Summary: Directed self-assembly of block copolymers has attracted interest from the semiconductor industry due to its potential for achieving semiconductor-relevant structures with a relatively simple and low-cost process. However, the kinetic trapping of self-assembling structures into defective states poses challenges for high-volume manufacturing. A study on the kinetics of defect annihilation in chemoepitaxy DSA revealed a statistical model that suggests all dislocations can be removed by sufficiently long annealing time. Further analysis showed that the distribution of defects is largely influenced by the role of guiding stripes.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Polymer Science
Maninderjeet Singh, Wenjie Wu, Monali N. Basutkar, Joseph Strzalka, Abdullah M. Al-Enizi, Jack F. Douglas, Alamgir Karim
Summary: The study demonstrates a rapid self-assembly technique for achieving vertical orientation of block copolymer films on unmodified substrates, leading to faster formation of ordered structures.
Article
Polymer Science
Jing Wang, Jiaqi Si, Junwei Zhu, Yiqing Nie, Yan Lu, Yongming Chen
Summary: A series of crystalline-coil block copolymers with different block ratios were synthesized to explore the impact of polymer compositions on self-assembly morphologies. The copolymers were found to self-assemble into various morphologies including lozenges, quadrilaterals, elongated hexagons, hexagonal platelets, saw blade platelets, and spindle micelles. Adjusting block ratios of the copolymers is a facile way to construct diverse morphologies of polymer materials.
Article
Chemistry, Multidisciplinary
Sujin Lee, Chae-Young Lee, Jang-Hoon Ha, Jongman Lee, In-Hyuck Song, Se-Hun Kwon
Summary: This study aims to increase the compressive strength of reticulated porous zirconia by optimizing process conditions and using additives. The effects of multiple slurry coating on microstructure and compressive strength were also explored. The results show a significant improvement in compression strength.
APPLIED SCIENCES-BASEL
(2022)
Article
Materials Science, Multidisciplinary
Hyun-Jae Woo, Woo-Jae Lee, Chang-Min Kim, Qimin Wang, Shihong Zhang, Yong-Jin Yoon, Se-Hun Kwon
Summary: The structural and electrical properties of PtRu bimetallic alloy thin films prepared via atomic layer deposition (ALD) can be effectively controlled by changing the deposition cycles of Pt and Ru, and the films can form well-mixed solid solutions after heat treatment.
Article
Polymer Science
Jaemin Park, Jiyun Nam, Myungeun Seo, Sheng Li
Summary: This study reports the synthesis and self-assembly of brush-linear diblock copolymers with variable side-chain length and density. By controlling the PEG chain length and the degree of substitution, brush-linear diblock copolymers with different side-chain lengths and densities were obtained. The study found that different solid-state morphologies can be formed at different PEG side-chain densities.
Article
Chemistry, Inorganic & Nuclear
Nam Young Ahn, Jooyeon Lee, Wonjune Yeo, Hyojin Park, Jiyun Nam, Min Kim, Myungeun Seo
Summary: We have developed a synthetic method for decorating the surface of metal-organic frameworks (MOFs) with polymers through postsynthetic modification. By reacting well-defined polymers with reversibly deactivated radical species at their chain end with vinyl-functionalized MOFs in the presence of a radical initiator, we can form a C-C bond between the polymer end and the functional group at the MOF ligand. We have successfully achieved four polymer@MOF composites through this method.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Kyoungmun Lee, Hyun-Ro Lee, Young Hun Kim, Jaemin Park, Suchan Cho, Sheng Li, Myungeun Seo, Siyoung Q. Choi
Summary: This study demonstrated the continuous generation of hydroxyl radicals in oil-confined aqueous microdroplets, enabling the synthesis of polymers at high reactant concentrations. The transport of hydroxyl radicals also facilitated polymerization reactions in the continuous oil phase. This interfacial phenomenon was successfully applied to the chain extension of polymers.
ACS CENTRAL SCIENCE
(2022)
Article
Chemistry, Physical
Woo-Jae Lee, Se-Hun Kwon
Summary: Ultrathin films or particles of atomic layer deposition (ALD) on high surface can improve the activity and durability of catalyst fields. In this study, a Pt catalyst is synthesized through ALD on carbon black whose surface is modified through treatment with citric acid. The acid-treated carbon exhibits rich oxidized functional groups and abundant defects but lower surface areas and pore volumes. After ALD Pt deposition, highly dense, uniform, and well-dispersed Pt nanoparticles (NPs) are observed on the acid-treated carbon, resulting in improved electrochemical activity and PEMFC performances.
PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION
(2023)
Article
Polymer Science
Chinnadurai Satheeshkumar, Howon Seo, Sujung Hong, Pilhan Kim, Myungeun Seo
Summary: In this study, a synthetic route based on radical polymerization was developed to produce a fluorescent monolithic hierarchically porous polymer composed of extended pi-conjugated triphenylene motifs. Microphase separation and removal of polylactide generated controllable mesopores and exposed micropores within the polymer network. The resulting porous monolith exhibited strong bluish fluorescence, which could be quenched upon exposure to nitroaromatic compounds.
Article
Chemistry, Multidisciplinary
Hyun Woo Park, Eunyeong Cho, Yun Zou, Sea Hoon Lee, Jae Ryung Choi, Sang-Bok Lee, Kyeongwoon Chung, Se Hun Kwon, Jeonghun Kim, Hee Jung Lee
Summary: Yttria-stabilized zirconia (YSZ) nanospheres were synthesized by calcination after adsorbing Y3+ ions into the pores of a zirconium-based metal-organic framework (MOF). The synthesized 3YSZ, 8YSZ, and 30YSZ nanospheres showed uniform sizes and shapes. Complex permittivity and permeability measurements in the K-band indicated that these materials have potential for use as low-k materials in high-frequency 5G communications.
Article
Nanoscience & Nanotechnology
Su-Young Park, Jung-Won An, Ji-Hu Baek, Hyun-Jae Woo, Woo-Jae Lee, Se-Hun Kwon, Susanta Bera
Summary: This study evaluates the activity and stability of in situ crystallized antimony-doped tin oxide (Sb-SnO2)@RuOx heterostructure nanosheets (NSs) for acidic water oxidation. The catalyst prepared by atomic layer deposition and heat treatment exhibits comparable activity but longer stability than the ex situ catalyst. The controlled interface stability of heterostructure catalysts plays a significant role in enhancing oxygen evolution reaction (OER) activity and stability.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Zhengtao Wu, Yintuan Zhang, Qimin Wang, Kwang-Ho Kim, Se-Hun Kwon
Summary: The microstructure and properties of WTi alloy films with different contents of Ti prepared by magnetron sputtering were investigated. The electrical resistivity increased with the increase in Ti content. The alloy film with 6.8 at.% Ti showed the highest temperature coefficient of resistance, which decreased gradually after thermal resistance tests and annealing treatment. The WTi films exhibited excellent stability in thermal resistance tests and have potential applications in temperature measurement of tools and dies.
APPLIED SCIENCES-BASEL
(2023)
Article
Nanoscience & Nanotechnology
Min-Ji Kim, Jong-Seong Bae, Myung-Jin Jung, Eunsong Jeon, Yiseul Park, Hasmat Khan, Se-Hun Kwon
Summary: Defect control in TiO2 thin films is challenging but crucial for improving photoelectrochemical (PEC) efficiency in water splitting processes. In this study, defective amorphous TiOx thin films were prepared by atomic layer deposition (ALD) at various growth temperatures. The defect concentration in the films was found to be controllable by adjusting the growth temperature during ALD, as analyzed by X-ray photoelectron spectroscopy and electron spin resonance spectroscopy. The light absorption properties of the films were characterized using ultraviolet-visible absorption spectroscopy. The film deposited at 200 degrees C exhibited the highest defect concentration and photocurrent density compared to other films. By carefully studying the light absorption efficiency, photogenerated charge separation efficiency, and charge transfer efficiency, the correlation between defect concentration and PEC activity in the prepared TiOx thin films was understood. This study provides insights into the PEC properties of defective amorphous ALD-TiOx thin films.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Materials Science, Coatings & Films
Sanghun Lee, Seunggi Seo, Woo-Jae Lee, Wontae Noh, Se-Hun Kwon, Il-Kwon Oh, Hyungjun Kim
Summary: The correlation between hydroxyl and the growth of ALD TiSiOx was investigated, and it was found that the presence or absence of hydroxyl at different temperatures leads to differences in growth characteristics.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Review
Polymer Science
Taeseok Oh, Suchan Cho, Changsu Yoo, Wonjune Yeo, Jinyeong Oh, Myungeun Seo
Summary: Polymerization-induced microphase separation (PIMS) is a method for synthesizing nanostructured block polymer materials, allowing for simultaneous nanostructuring during polymerization. PIMS, with its in situ cross-linking feature, offers a facile route to nanostructured block polymer thermosets in combination with various polymerization techniques.
PROGRESS IN POLYMER SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Byung-Hyun Shin, Dohyung Kim, Doo-In Kim, Wookjin Lee, Se-Hun Kwon
Summary: The demand for Li-ion batteries has increased due to the growing need for electric vehicles and electronic devices. Super duplex stainless steel (SDSS) is suitable for Li-ion batteries due to its strength and corrosion resistance. This study focuses on Ni plating of heat-treated SDSS and finds that solution annealing can optimize the plating and enhance corrosion resistance.
Article
Chemistry, Multidisciplinary
Jongmin Park, Eunsook Park, Siyoung Q. Choi, Jingxian Wu, Jihye Park, Hyeonju Lee, Hyungjun Kim, Haeshin Lee, Myungeun Seo
Summary: Bioadhesives are becoming increasingly important in medical science. However, developing adhesive materials that combine strong adhesion, biocompatibility, and biodegradation remains challenging. In this study, a biocompatible and biodegradable block copolymer-based waterborne superglue was developed for follicle-free hair transplantation. The adhesive showed step-wise increase in adhesion strength and significantly enhanced mechanical properties compared to the conventional formulation.
