Sang Kyoo Lim

Sang Kyoo Lim
Daegu Gyeongbuk Institute of Science and Technology | DGIST · Department of Convergence Studies

Doctor of Engineering

About

80
Publications
3,952
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
2,080
Citations

Publications

Publications (80)
Article
In this study, the effects of the morphology of components on the performance of a piezoelectric nanogenerator were investigated. Polyvinylidene fluoride (PVDF) fibers with biomimetic cross-sectional morphologies inspired by plants were fabricated by integrating melt spinning, winding, and corona poling. The cross-sectional morphology of the PVDF f...
Article
Full-text available
Among the starting materials of thermoplastic polyurethanes (TPUs), it was confirmed that succinic acid-based polyester biopolyols having different molecular weights (Mn = 1000, 2000, and 4000) affect the physicochemical properties of the final polymer significantly. Bio-TPUs synthesized through a solvent-free one-shot polymerization process were s...
Article
Recently, significant progress has been made in the development of new techniques for the fabrication of mechanically durable, bright, and deformable electroluminescent devices, leading to the emergence of various technologies, such as soft robots, actuators, flexible/stretchable/wearable electronics, and self-healable devices. However, these devic...
Article
Full-text available
In this study, highly porous carbon fiber was prepared for hydrogen storage. Porous carbon fiber (PCF) and activated porous carbon fiber (APCF) were derived by carbonization and chemical activation after selectively removing polyvinyl alcohol from a bi-component fiber composed of polyvinyl alcohol and polyacrylonitrile (PAN). The chemical activatio...
Article
Stretchable yarn/fiber energy storage devices with a high energy density are highly beneficial for use in wearable applications. Although some studies on stretchable fiber batteries have been conducted, the development of fiber batteries that combine outstanding stretchability with a high energy storage capacity has been restricted by the tradeoff...
Article
Full-text available
The development of a highly sensitive gas sensor for toxic gases is an important issue in that it can reduce the damage caused by unexpected gas leaks. In this regard, in order to make the sensor accurate and highly responsive, we have investigated which morphology is effective to improve the sensitivity and how the deposited nanoparticle affects t...
Article
A colorimetric hydrogen sensor has great potential for accurately detecting and monitoring the leakage of hydrogen gas on account of its fast color change in contact with hydrogen gas. However, for the practical application of the sensor, such as in gas detection systems in clothing, the flexibility and stability of the sensor need to be improved....
Article
In this study, the morphological effects of ZnO on the antimicrobial and deodorant activities of synthetic fibers were investigated. Three different polyethylene terephthalate (PET)/ZnO filaments were prepared by incorporating various ZnO nanostructures (rods, plates, and spheres) into PET filaments via a melt-spinning process. The antimicrobial ac...
Article
In the recent remarkable advances in soft electronic systems, light-emitting functions play a prominent role. In particular, polymer composite systems with embedded luminescent particles have attracted considerable attention as a luminescent component owing to their flexibility and simple fabrication. However, most flexible composite-based electrol...
Article
Full-text available
For the fast and easy detection of carbon monoxide (CO) gas, it was necessary to develop a CO gas sensor to operate in low temperatures. Herein, a novel Cu/CuO-decorated ZnO hollow nanofiber was prepared with the electrospinning, calcination, and photodeposition methods. In the presence of 100 ppm CO gas, the Cu/CuO-photodeposited ZnO hollow nanofi...
Article
Finger skin electronics are essential for realizing humanoid soft robots and/or medical applications that are very similar to human appendages. A selective sensitivity to pressure and vibration that are indispensable for tactile sensing is highly desirable for mimicking sensory mechanoreceptors in skin. Additionally, for a human-machine interaction...
Article
Full-text available
Highly deformable and electrically conductive fibres with multiple functionalities may be useful for diverse applications. Here we report on a supercoil structure (i.e. coiling of a coil) of fibres fabricated by inserting a giant twist into spandex-core fibres wrapped in a carbon nanotube sheath. The resulting supercoiled fibres show a highly order...
Article
In this study, we synthesized cross-linked poly methyl methacrylate beads and cross-linked fluorinated poly methacryalte copolymer (F-cPMMA) beads by the dispersion polymerization method with methyl methacrylate monomer, ethylene glycol dimethacrylate, and 2,2,2-trifuloroethyl methacrylate. The size of cross-linked PMMA and F-cPMMA beads was about...
Article
We have synthesized new colorimetric hydrogen-sensing materials, PdO/metal oxide hybrid nanoparticles, in which palladium oxide was loaded upon surface of substrate materials via an acid-base reaction between a H2PdCl4 solution and substrate materials, ZnO, MgO, TiO2, and SiO2 respectively at 25 °C. The colorimetric hydrogen gas sensing properties...
Article
Full-text available
We demonstrate wide colour tunability of polydimethylsiloxane-based alternating-current-driven electroluminescent devices with intrinsically stretchable characteristics achieved by simply modulating the electrical frequency. By employing both a screen-printed emitting layer and frequency-dependent colour tuning of ZnS:Cu-based phosphors, we demonst...
Article
A thrombus (blood clot), composed mainly of activated platelets and fibrin, obstructs arteries or veins, leading to various life-threatening diseases. Inspired by the distinctive physicochemical characteristics of thrombi such as abundant fibrin and the elevated level of hydrogen peroxide (H2O2), we developed thrombus-specific theranostic (T-FBM) n...
Article
A mechanoluminescent fiber that is capable of emitting light and can potentially be powered by human motion instead of a battery is demonstrated by Soon Moon Jeong, Sang Kyoo Lim, and co-workers in article number 1700126. The cover image shows that the mechanoluminescent light is generated by dynamic human motions inducing mechanical stress in a me...
Article
Much effort is being directed at developing wearable devices because they offer the potential combination of real-time personal communication and convenient portability. In this sense, communicative textiles that can sense and respond to changes in their environment, that is, smart textiles, are attracting attention because they are easy to integra...
Article
Plastic optical fiber fabrics are widely utilized as efficient support materials owing to their high flexibility. In this study, we have investigated a remote photocatalysis system using modified plastic optical fiber fabrics. We successfully deposited TiO2 onto a modified plastic optical fiber fabric using the dip-coating method. The drying temper...
Article
We fabricated a new type of flexible organic-inorganic hybrid material (ZnO/NCPF) by loading ZnO nanostructure on a polyethylene terephthalate fabric with Ni–Cu–Ni conducting layer (NCPF) by an electrodeposition method. This material was demonstrated to be able to operate as a flexible photo-sensor under solar light irradiation. The optimized sampl...
Article
Crystalline ZnO rods rooted on manifold carbon nanofiber (CNF) paper were synthesized via electrodeposition of ZnO onto electrospun CNF paper (similar to 300 mm thick) followed by oxidative annealing. The morphology of the ZnO deposited on the conductive CNF paper can be tailored to be polycrystalline rods with convex-shaped ends at a high Zn2+ pre...
Article
In this study, we prepared horn-like ZnO structures on carbon films (ZnO/CF) by electrodeposition and decorated the ZnO horns with different metals (Ag, Au, and Pt) via photodeposition (M–ZnO/CF). Using M–ZnO/CF as photocatalysts, we examined ways to enhance solar hydrogen production from various points of view, such as modifying the intrinsic phys...
Article
Solar H2 production by photocatalytic water splitting is a promising technology that permits direct H2 production from the clean and abundant resources of water and solar light. We successfully fabricated trilayer heterostructures of CdS/carbon nanofiber (CNF) mat/Pt-deposited TiO2 (Pt-TiO2) for solar H2 production. The CNF mat was prepared by elec...
Article
Solar hydrogen production by ZnO electrodeposited onto carbon films was systematically investigated by controlling the amount of the deposited ZnO, property of carbon, and surface activation by KOH treatment. Carbon films have been prepared by polymer solution casting method using PAN solution, and subsequently annealing process. The surface of car...
Article
Highly porous carbon fibers based on rice straw and paper mulberry have been successfully prepared via wet spinning and carbonization process. From the comparison of the morphological structure and specific surface area, the porous carbon fibers derived from rice straw shows a high specific surface area of 2260 m2/g. This material exhibits excellen...
Article
In this work, we tried to enhance anti-bacterial activity of fabric fibers by controlling the shape of filaments, such as tetragonal and cross-pillar, which led to an increase of the surface portion of filaments. With this purpose, silver and platinum nanoparticles were immobilized on the surface of TiO2 nanoparticles within tetragonal and cross-pi...
Article
Semiconductor-based photocatalysts for solar H-2 generation has attracted significant attention because of its great potential for low-cost and clean H-2 production. In this study, we prepared a core-shell structured Au@CdS on TiO2 nanofibers (Au@CdS/TNF) and investigated its photocatalytic H-2 production under visible (lambda > 420 nm) irradiation...
Article
Aluminum doped ZnO (AZO) nanorods were synthesized by microemulsion method with different types of surfactants. The phase and the morphology of the above nanorods were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). SEM observations showed that the ZnO nanorods had diameters around about 50–200 nm and lengths up to s...
Article
Photocatalysis-based solar hydrogen (H2) has garnered attention as a renewable energy carrier, yet the technology is still immature. For practical operation of photocatalytic H2 production, we fabricated a novel heterojunction of CdS-loaded flexible carbon nanofiber (CNF) mats. CNF mats were prepared by electrospinning and carbonization. CdS nanopa...
Article
ZnO particles with rod and plate configurations were synthesized using a solvothermal method using zinc acetate and zinc chloride, respectively. The surface of the as-synthesized ZnO rods and plates were characterized using various analysis tools (XRD, XPS, photoluminescence, FE-SEM, HR-TEM, BET, and UV-vis) and their photocatalytic activities were...
Article
Core–shell materials have been developed extensively because of their advanced properties and multifunctionality. Many approaches involving different synthesis techniques have been used for the preparation of various core–shell nanostructures. In this study, we synthesized core–shell-structured carbon nanofiber (CNF)-titanate nanotubes (TiNT) by el...
Article
This study demonstrates that multi-walled carbon nanotubes (CNTs) effectively catalyzes photocatalytic hydrogen production in heterojunction suspensions under solar visible light (AM 1.5G; λ > 420 nm). Due to the high catalytic activity of CNTs, use of Pt can be significantly reduced. For this, quaternary composites (CdS/TiO2/Pt/CNTs) are prepared...
Article
Poly (ethylene terephthalate)(PET)/Al2O3 nanocomposites via in situ polymerization were studied. The nanoparticle loading was varied from 0.3 to 1 wt.%. From the DSC results, no significant differences were recorded for melting temperatures. However, simple added PET/Al2O3 nanocomposites slightly changed to the lower melting temperature. Morphology...
Article
Gallium-doped ZnO (GZO) nanorods were synthesized by microemulsion method with different types of surfactants. The phase and morphology of the above nanorods were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). SEM obse...
Article
Nanocomposite films of poly(ethylene terephthalate)(PET) and nano titania(TiO_2) were prepared by melt compounding with a twin-screw extruder followed by hot pressing for the purpose of investigating antibacterial activity. FE-SEM, EDS and XRD measurements confirmed that nano TiO_2 was successfully dispersed at the level of individual particles in...
Article
Gold, silver, and platinum nanoparticles were immobilized on the surface of TiO2 in the sheath part of bi-component filaments. The processes involved include the spinning process used to prepare polyethylene terephthalate (PET)/PET-TiO2 bi-component filaments and the photocatalytic deposition process of gold, silver and platinum nanoparticles. The...
Article
Titanate nanotubes (TiNTs) were prepared by alkaline hydrothermal processing. The TiNTs are thermodynamically unstable and easily transformed to the titania phase by heat or acid treatment. These phase transformations are affected by the preparation conditions. In this study, we investigated the effects of using the washing process to modify the so...
Article
Hydrothermally prepared titanate nanotubes are known to be thermodynamically unstable and to be easily transformed to the titania phase by heat or acid treatment, which is accompanied by the destruction of the nanotube structures. Surface modification of titanate nanotubes is expected to retard the phase-transition reactions from titanate nanotubes...
Article
Directionally grown TiO(2) nano-architectures can serve as effective platforms for photogenerated charges to flow vectorially through the architecture framework, promising an unexpectedly high efficiency. This study demonstrates that directionally aligned TiO(2) nanofibers (TNF) obtained via a simple rearrangement of randomly scattered TiO(2) nanop...
Article
Nanostructured titanates were prepared by alkaline hydrothermal processing. The titanates were transformed to the anatase particles at low concentrations of acid, whereas the rutile rods were produced from the titanates at high concentrations of acid. These changes were more retarded in the titanate nanofiber product than in titanate nanotubes prod...
Article
The purpose of this study is to search for effective dopants and their optimal combinations to improve the electrocatalytic activity of the SnO2 electrode for the remediation of aqueous pollutants. For this purpose, Sb was selected as the primary dopant for SnO2 and six elements (Fe(III), Ni(II), Co(II), Ru(III), Ce(III), and Pd(II)) were also intr...
Article
In this work, we have synthesized Titanate nanotube(TiNT) and Layered Double Hydroxide(LDH) nanoparticles and studied about their applicable properties as inorganic filler due to their high porous structure, and then the obtained nanoparticles were dispersed in exfoliated vermiculites, in order to apply this technology to the fabrication process of...
Article
One-dimentional nanostructures in the form of nanorods, nanowires, nanofibers or nanotubes, appear as an exciting research area for their great potential of applications. Zinc oxide is an n-type semiconductor that has been well known for its applications in pigments, rubber additives, gas sensors, solar cells, varistors, and optical devices. In thi...
Article
Zinc oxide nanorods with different surface area were synthesized by surfactant assisted microemulsion method. The alkyl chain length of surfactant would affect aspect ratio of ZnO nanorods. ZnO nanorods synthesized by ethyl benzene acid sodium salt (EBS), which is surfactant with short alkyl chain length, show higher aspect ratio than ones by dodec...
Article
Full-text available
In this study, UV photodetectors based on a network of aluminium-doped zinc oxide (AZO) nanowires were manufactured at a low cost; for this purpose, a fast and simple fabrication process that involved dropping nanowires dispersion solution was employed instead of the conventional e-beam lithography process that is used to manufacture single nanowir...
Article
Full-text available
This study was conducted in order to observe the changes in the ultraviolet (UV) photodetection characteristic when TiO2 nanoparticles are modified on the surface of an aluminum-doped zinc oxide (AZO) nanowire in an AZO nanowire network with enhanced conductivity. According to the experiment results, the UV photosensitivity under a bias of 5 V was...
Article
Currently, the use of fuel cell electrodes containing Pt catalysts has been limited due to technological problems in this system, primarily the system's high cost. The improvement of Pt catalyst use has been achieved by changes in the Pt immobilization method. In this study, we have studied Pt immobilization on carbon nanofiber composites using the...
Article
The development of a high-efficiency TiO2 photocatalyst is of great importance to a variety of solar light conversion and application fields; the desired high efficiency can be achieved by employing well-controlled TiO2 nanoarchitectures. In this study, we have successfully synthesized well-ordered and aligned high surface area mesoporous TiO2 nano...
Article
Mesoporous In2O3 nanofibers with a high surface area were synthesized by calcining electrospun polyvinyl alcohol (PVA)/indium acetate composite fibers. A PVA solution and indium acetate were mixed and electrospun. After calcining the PVA/indium acetate composite nanofiber precursor, mesoporous In2O3 nanofibers were successfully formed. These nanofi...
Article
Aluminium doped ZnO (AZO) nanorods were synthesized by microemulsion method with different types of surfactants. Scanning electron microscopy observations show that the ZnO nanorods have diameters around about 80 nm and lengths up to several micrometers. The room temperature photoluminescence (PL) spectrum of AZO nanorods exhibited a sharp and stro...
Article
The study of high efficiency electrochemical water treatment systems is of great importance in contributing to a sustainable water supply. In this study, we prepared RuO2/Ti and Sb–SnO2/Ti electrodes and investigated their electrocatalytic activities for the oxidation of water and three model substrates (methylene blue, acid orange 7, and 4-chlorop...
Article
Full-text available
We carried out a study on the change in pore wall thickness depending on the current density in p-type silicon. We attempted the formation of a uniform macropore or nanorod array with a high aspect ratio in p-type silicon by electrochemical etching through the optimization of the hydrogen fluoride (HF)/organic electrolyte composition and the design...
Article
TiO2-embedded carbon nanofibers (TiO2/CNF) have been prepared by a simple method. TiO2-embedded polyacrylonitrile fibers (TiO2/PAN) were first prepared from a PAN solution containing TiO2 particles by a simple electrospinning method, and subsequent carbonization and further oxidation of these led to TiO2/CNF and oxidized TiO2/CNF (Ox-TiO2/CNF), res...
Article
In this work, silver nanoparticles were embedded in electrospun organic/inorganic composite nanofibers consisting of PAN and TiO2 through photocatalytic reduction of the silver ions in silver nitrate solutions under UV irradiation. The morphology and diameter of PAN/TiO2 composite nanofibers could be controlled by varying the initial contents of Ti...
Article
Three polyester films with different repeating units—poly(lactic acid) (PLA), poly(ethylene terephthalate) (PET), and poly(oxybenzoate-co-oxynaphthoate) (PBN)—were modified by plasma, and the way in which the chemical compositions of the polymer chains influenced the plasma modification was investigated with contact-angle measurements and X-ray pho...
Article
Poly(oxybenzoate-co-oxynaphthoate) (POCO) film surfaces were modified with remote oxygen plasma, and the effects of the modification on the adhesion between the copper layer and POCO were investigated. The remote-oxygen-plasma treatment led to a noticeable decrease in the contact angle, which was mainly due to the CO functional groups on the surfac...
Article
- Ethylene-co-tetrafluoroethylene copolymer (ETFE) films were modified by four plasmas: direct and remote H2 plasmas and direct and remote O2 plasmas; and the hydrophobic recovery process of these plasma-modified surfaces was investigated using water contact angle measurements and angular XPS. The water contact angle measurements showed important a...
Article
The surface modifications of ethylene-co-tetrafluoroethylene (ETFE) surfaces by six plasmas (direct H2, Ar, and O2 plasmas and remote H2, Ar, and O2 plasmas) were investigated with two questions in mind: (1) what plasma could effectively modify ETFE surfaces and (2) which of the CF2CF2 and CH2CH2 components in ETFE was selectively modified? The pla...
Article
Regenerated cellulose fibers from rice straws with a diameter of 10 to 25 μm and initial modulus of 11 to 13 GPa were prepared by wet spinning in rice straw/N-methylmorpholine-N-oxide (MMNO) solution. X-ray diffraction analysis indicates that the rice straw regenerated fibers are classified as cellulose (II). This observation indicates a potential...
Article
Regenerated cellulose fibers from rice straws with a diameter of 10 to 25 μm and initial modulus of 11 to 13 GPa were prepared by wet spinning in rice straw/N-methylmorpholine-N-oxide (MMO) solution. X-ray diffraction analysis indicates that the rice straw regenerated fibers are classified as cellulose (II). From the regenerated cellulose fiber bas...
Article
In this study, the novel morphology of polypropylene (PP) and poly(ethylene-co-vinyl alcohol) (EVOH) blend fibers is described. More precisely, the blend fibers of PP–EVOH containing a small amount of EVOH (1, 3, 5, 7, and 9% by weight), with and without epoxy (1 wt %), have been melt-spun at a constant spinning velocity (500 m/min). For the as-spu...
Article
EVA was blended with phenoxy over the whole range of composition using a twin-screw Brabender. Two-phase separation caused by EVA crystallization was observed in the EVA-rich blends and the dispersed domain of EVA was not clearly shown in the phenoxy-rich blends. Differential scanning calorimetry (DSC) showed that the glass transition temperature (...
Article
A series of polyurethanes based on Poly(oxytetramethylene)glycol (PTMG), 4,4′-diphenylmethane diisocyanate (MDI) and 2,2-bis-[4-(2-hydroxyethoxy)phenyl]propane (BHPP) was synthesized by two-step solution polymerization varying PTMG soft segment length and hard segment content. Thermal and dynamic mechanical properties were studied by DSC and DMA. S...
Article
It is often pointed out that low water absorption and moisture permeability are drawbacks of polypropylene (PP). In this study, blending with an amorphous polymer was used to modify PP. For improving the properties of PP without any property depression, PP was blended with phenolic resin-Novolak type (PRN). PP/PRN blends were investigated by a cont...
Article
Poly(4-morphonylphosphonate of bisphenol A) (PMPB) was synthesized by the interfacial polymerization of phosphonic dichloride, 4-morphonyl (PDCM) and bisphenol A in an aqueous-organic biphasic system. Synthesized polymer was found to be PMPB by using EA, FT-IR and H-NMR. Prepared PMPB had different values of molecular weight depending on the solubi...
Article
Layered double hydroxide(LDH) compounds have attracted a great attention because of their layered structure and high anion exchange capacity, which can make various technical applications. LDHs are the only known inorganic materials with positive layer charge, in which the interlayer anions can be replaced by ion-exchange processes. Their structura...
Article
Coordinated polymer particles(CPPs) have attracted a great attention because of their high surface area and fundamentally interesting unique structure, which allow for applications in non-linear-optics,[1] catalysis,[2] gas storage,[3, 4] and molecular recognition.[5] A sophisticated understanding of coordination polymer particle formation, as well...