• Journal of Adhesion and Interface
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• v.6 no.1
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• pp.7-10
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• 2005

Condensation control of nano-particles has become important in order to fabricate minute condensed structures. In this study, we focus our attention on condensation mechanism of polymer aggregates in a resist film. The polymer aggregate is structural component of a resist material which is used in lithography process. The condensation nature of polymer aggregates in the resist film surface is observed by using atomic force microscope (AFM). By using the AFM, the condensation of polymer aggregates can be observed clearly. The condensation of polymer aggregate strongly affects to precise fabrication of resist pattern below 100nm size. The interaction force among polymer aggregates can be analyzed based on Derjaguin approximation. We also discuss about condensation nature of polymer aggregates in the resist film surface with the help of micro sphere model.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.5
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• pp.516-521
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• 2011

The basilar membrane, an important functional part of the cochlea, is responsible for spectral separation of vibration signals transmitted from the stapes. In current study, scaled-up polymer membranes designed by mimicking the human basilar membrane were used for investigation of the frequency-separation characteristic. Displacement field formed on each polymer membrane was acquired by Laser Doppler scanning vibrometer and post-processed frequency-wise. The locations of the maximum displacement along the centerline were identified and collected for individual frequency range to produce the frequency-position map of individual polymer membrane. The influences of the membrane thickness and material properties on the variation of the frequency separability were discussed.

• Polymer Science and Technology
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• v.22 no.5
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• pp.460-466
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• 2011

• Journal of the Korean Society for Precision Engineering
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• v.29 no.1
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• pp.33-40
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• 2012

The scaffold serves as 3D substrate for the cells adhesion and mechanical support for the newly grown tissue by maintaining the 3D structure for the regeneration of tissue and organ. In this paper, we proposed integrated scaffold fabrication system using multi-axis rapid prototyping (RP) technology. It can fabricate various types of scaffolds: arbitrary sculptured shape, primitive shape, and tube shape scaffolds by layered dispensing biocompatible/ biodegradable polymer strands in designated patterns. In order to fabricate the 3D scaffold, we need to generate the plotting path way for the scaffold fabrication system. We design a data processing program - scaffold plotting software, which can convert the 3D STL file, primitive and tube model images into the NC code for the system. Finally, we fabricated the customized 3D scaffolds with high accuracy using the plotting software and the fabrication system.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.2
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• pp.63-72
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• 2005

In this study, the physical and mechanical properties of steel fiber reinforced lightweight polymer concrete were investigated experimentally with various steel fiber contents. All tests were performed at room temperature, and stress-strain curve and load-deflection curve were plotted up to failure. The unit weight of steel fiber reinforced lightweight polymer concrete was in the range of $1,020{\sim}1,160\;kg/m^3$, which was approximately $50\%$ of that of the ordinary polymer concrete, The compressive strength, splitting tensile strength, flexural toughness and flexural load-deflection curves after maximum load were shown with increase of steel fiber content. The stress-strain curves of steel fiber reinforced lightweight polymer concrete were bilinear in nature with a small transition zone, Based on these results, steel fiber reinforced lightweight polymer concrete can be widely applied to the polymer composite products.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.11-15
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• 2003

In order to suppress a repulsive interfacial energy between hydrophilic clay and hydrophobic polymer matrix in preparing a polymer/clay nanocomposite, a third component of amphiphilic nature such as poly($\varepsilon$-caprolactone) (PCL) was introduced into the model system of styrene-acrylonitrile copolymers (SAN)/Na-montmorillonite. Once $\varepsilon$-caprolactone was polymerized in the presence of Na-rnontmorillonite, the successful ring-opening polymerization of $\varepsilon$-caprolactone and the well-developed exfoliated structure of PCL/Na-montmorillonite mixture were confirmed, Thereafter, SAN was melt-mixed with PCL/Na-montmorillonite nanocomposite, which resulted in that SAN matrix and PCL fraction were completely miscible to form homogeneous mixture with retention of the exfoliated state of Na-montmorillonite, exhibiting that PCL effectively stabilizes the repulsive polymer/clay interface and contributes the improvement of mechanical properties of the nanocomposites.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.289-289
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• 2011

The conducting polymer thin films were deposited using the gas phase method which known as molecular layer deposition (MLD). Terephthalaldehyde (TPA) and p-phenylenediamine (PD) were used as monomers to deposit conducting polymer. Self-terminating nature of TPA and PD reaction were demonstrated by growth rate saturation versus precursors dosing time. Infrared spectroscopic and X-ray photoelectron spectroscopy were employed to determine the chemical composition and state of conducting polymer thin films. Layer by layer growth and polymerization of thin films can be showed by shifting of absorption edge using UV-VIS spectroscopy. This conducting polymer fabricated by using MLD method gives the opportunity to develop new hybrid materials by combining inorganic materials in nanoscale.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.640-643
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• 1999

This paper presents the results of multi-stress chamber experiments done to examine the tracking and erosion performance of polymer insulator. Multi-stress testing is able to demonstrate deficiencies of polymer insulator materials and designs, including the nature of interfaces in insulation design. Therefore, multi-stress testing is believed to a suitable test for evaluating the aging performance of polymer insulator designs. We have nvestigated IEC 61109 Annex C for estimating long time performance of polymer insulator.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.3
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• pp.15-20
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• 2016

In an effort to overcome the weakness of aerogel, polymer aerogels have been prepared by copolymerizing the different types of monomers through sol-gel process. Polymerizing the successive phase of a high internal phase emulsion, which has interconnected porous structure, porous polymer aerogel can be manufactured. In this paper, we use the styrene/divinylbenzene chain as a basic monomer structure, and additionally use 2-ethylhexyl methacrylate (2-EHMA) or 2-ethylhexyl acrylate (2-EHA) as monomers for distinguishing the visible mechanical properties of synthesized polymer aerogel. We can observe the different tendency of polymer aerogels by kinds of monomer or ratio. Flexibility and microstructure can be changed by the types of monomer. EHA polymer aerogel shows high flexibility and thin microstructure, and EHMA polymer aerogel shows high hardness and thick microstructure. EHA/EHMA polymer aerogel shows the intermediate nature between them. By utilizing the mechanical properties of three types of polymer aerogels to adequate situation or environment, polymer aerogels could be used as drug agent, ion exchange resin, oil filter and insulator, and so on.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2332-2334
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• 1999

This paper presents the results of multi-stress chamber experiments done to examine the tracking and erosion performance of polymer insulator. Multi-stress testing is able to demonstrate deficiencies of polymer insulator materials and designs including the nature of interfaces in insulation design. Therefore, multi-stress testing is believed to a suitable test for evaluating the aging performance of polymer insulator designs. We have investigated IEC 61109 Annex C for estimating long time performance of polymer insulator.