• 한국가시화정보학회:학술대회논문집
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• 2005.12a
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• pp.89-92
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• 2005

A microcapsule for drug delivery was successfully produced by utilizing the flow-through droplet-based supramolecular self-assembly in a crossed microchannel network. The PS-b-PMMA block copolymer synthesized atom transfer radical polymerization (ATRP) was initially formed as microdroplets and after the evaporation process it turned to spherical capsule by polymer self-assembly of the micro domains. The characteristics were studied using various analysis methods.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.312-312
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• 2006

Block copolymers with well-defined nanoscopic structures have recently gained much attention for their potential uses as functional nanostructures. Here, we show that nanoporous templates made from polystyrene-block-poly (methyl methacrylate) (PS-b-PMMA) satisfy a novel design concept. At first, arrays of nanoscopic cylindrical microdomains oriented normal to the surface can easily be prepared. Then, we fabricated ultra high density arrays of conducting polymer as poly(pyrrole) (Ppy) and poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires with diameters of $25{\sim}40\;nm$ on the ITO glass by electropolymerization of the monomers inside nanoholes. These high density arrays of conducting polymer nanowires could be used as P-type materials for photovoltaic devices.

• Journal of Magnetics
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• v.13 no.2
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• pp.53-56
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• 2008

This study proposes a simple nano-patterning process for the fabrication of magnetic nanodot arrays on a large area substrate. Ni nanodots were fabricated on a large area (4 inches in diameter) Si substrate using the soft lithographic technique using self-assembled surface micelles of Polystyrene-block-Poly(methyl methacrylate) (PS-b-PMMA) diblock copolymer formed at the air/water interface as a mask. The hexagonal array of micelles was successfully transferred to a Ni thin film on a Si substrate using the Langmuir-Blodgett technique. After ion-mill dry etching, a magnetic Ni nanodot array with a regular hexagon array structure was obtained. The Ni nanodot array showed in-plane easy axis magnetization and typical soft magnetic properties.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.09a
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• pp.183-187
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• 2005

Thin films of diblock copolymers may be suitable for semiconductor device applications since they enable patterning of ordered domains with dimensions below photolithographic resolution over wafer-scale area. We obtained nanometer-scale cylindrical structure of dibock copolymer of polystyrene-block-poly(methylmethacrylate), PS-b-PMMA, also demonstrate pattern transfer of the nanoporous polymer using both reactive ion etching. The size of fabricated naonoholes were about 10 nm. Fabricated nanopattern surface was observed by field emission scanning electron microscope (FESEM).

• Journal of Photoscience
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• v.10 no.2
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• pp.203-208
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• 2003

Two coupled molecules were successfully synthesized by condensation of amine-donor-substituted barbituric acid derivativies as nonlinear optical chromophores. A flexible spacer of the alkyl chain with different lengths of carbon chains (5 and 6 carbons) was introduced between two chromophores, which prevented crystallization and aggregation of molecules. Two coupled molecules (B-Cn-B, n=5, 6) had glass-transition temperatures on a second heating around 81 and 76$^{\circ}C$ without melting points, respectively. To explore the linear optical properties, thin-films were prepared and examined by a photometry method using Nd:YVO$_4$ CW laser. Also, microscopic and macroscopic nonlinear optical properties were measured by Hyper-Rayleigh Scattering (HRS) and the Maker Fringes method using Nd:YAG ps pulse laser, respectively. In spite of the moderate hyperpolarizabilities of coupled molecules, the second order NLO coefficient (d$\_$33/) was larger than the conventional Disperse Red 1 doped PMMA polymeric system.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.3
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• pp.33-38
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• 2021

Recently, rollable and foldable displays are attracting great attention in the flexible display market due to their excellent form factor. To predict and prevent the mechanical failure of the display panels, it is essential to accurately understand the mechanical properties of brittle SiN_x thin films, which have been used as an insulating film in flexible displays. In this study, tensile properties of the ~130 nm- and ~320 nm-thick SiN_x thin films were successfully measured by coating a ~190 nm-thick organic nano-support-layer (PMMA, PS, P3HT) on the fragile SiN_x thin films and stretching the films as a bilayer state. Young's modulus values of the ~130 nm and ~320 nm SiN_x thin films fabricated through the controlled chamber pressure and deposition power (A: 1250 mTorr, 450 W/B: 1000 mTorr, 600 W/C: 750 mTorr, 700 W) were calculated as A: 76.6±3.5, B: 85.8±4.6, C: 117.4±6.5 GPa and A: 100.1±12.9, B: 117.9±9.7, C: 159.6 GPa, respectively. As a result, Young's modulus of ~320 nm SiN_x thin films fabricated through the same deposition condition increased compared to the ~130 nm SiN_x thin films. The tensile testing method using the organic nano-support-layer was effective in the precise measurement of the mechanical properties of the brittle thin films. The method developed in this study can contribute to the robust design of the rollable and foldable displays by enabling quantitative measurement of mechanical properties of fragile thin films for flexible displays.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.24.2-24.2
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• 2009

Nanostuctures such as nanodot and nanowire have been extensively studied as building blocks for nanoscale devices. However, the direct growth of the nanostuctures at the desired position is one of the most important requirements for realization of the practical devices with high integrity. Self-assembled nanotemplate is one of viable methods to produce highly-ordered nanostructures because it exhibits the highly ordered nanometer-sized pattern without resorting to lithography techniques. And selective epitaxial growth (SEG) can be a proper method for nanostructure fabrication because selective growth on the patterned openings obtained from nanotemplate can be a proper direction to achieve high level of control and reproducibility of nanostructucture fabrication. Especially, SiGe has led to the development of semiconductor devices in which the band structure is varied by the composition and strain distribution, and nanostructures of SiGe has represented new class of devices such nanowire metal-oxide-semiconductor field-effect transistors and photovoltaics. So, in this study, various shaped SiGe nanostructures were selectively grown on Si substrate through ultrahigh vacuum chemical vapor deposition (UHV-CVD) of SiGe on the hexagonally arranged Si openings obtained using nanotemplates. We adopted two types of nanotemplates in this study; anodic aluminum oxide (AAO) and diblock copolymer of PS-b-PMMA. Well ordered and various shaped nanostructure of SiGe, nanodots and nanowire, were fabricated on Si openings by combining SEG of SiGe to self-assembled nanotemplates. Nanostructure fabrication method adopted in this study will open up the easy way to produce the integrated nanoelectronic device arrays using the well ordered nano-building blocks obtained from the combination of SEG and self-assembled nanotemplates.

• Polymer(Korea)
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• v.35 no.3
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• pp.238-243
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• 2011

Organic/inorganic hybrid materials have a lot of interest in various areas due to their fascinating properties. To control the location and dispersion of inorganic nanoparticles within polymer matrix. thiol-terminated polymeric ligands have been widely used to tune the surface property of nanoparticles. However, the specific binding between the thiol functional group and metal is unstable with increasing temperature. To archive the thermally-stable Au nanoparticles, we previously synthesized various UV-crosslinkable polymeric ligands, which have different compositions of polar, UV-crosslinkable azide unit comparing to non-polar 스티렌 units. After crosslinking the Au nanoparticles, it was found that the nanoparticles had superb stability at high temperature (above $180^{\circ}C$). In this work, we used thermally-stable Au nanoparticles to control the location within the polymer matrix. By changing the amount of polar azide units in the polymeric ligands, we could precisely control the location of nanoparticles from one domain to the interface of block copolymer templates.