• Journal of the Korean Vacuum Society
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• v.1 no.1
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• pp.139-144
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• 1992

Abstract-Polyimide (PI) thin films were deposited by the ionized cluster beam deposition (ICBD) technique. Imidization and crystallization of PI films were investigated using transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR). PI films deposited under optimum conditions showed a maximum imidization and good crystal structure, which are superior to those of the films fabricated by other techniques.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.139-142
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• 1995

Polyimide(PI) thin films are fabricated by vapor deposition polymerization(VDP) from PMDA and DDE. The IR spectrum show that PAA the films are changed into PI films by curing. The activation energy of PI films is estimated to be 0.32 [eV] at the electric field of 0.133 [Mv/cm]. The resistivity is about 4.5${\times}$10$\_$16/ [$\Omega$$.$cm] at room temperature.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.204-204
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• 2006

The interfacial interaction along with microstructure and some properties of the polyimide(PI)/silica or polyimide/silsesquioxane hybrid nanocomposites will be discussed with reviewing recent publications including our own works. Poly(vinyl silsesquioxane) (PVSSQ), aminosilane (APS), and titania can effectively play vital roles to compatibilize the PI/silica hybrid composites by enhancing interfacial interaction or reducing agglomeration of large domains, which helps the formation of nanocomposites for the PI/silica hybrid system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05a
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• pp.202-205
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• 2004

We investigated the electro-optical(EO) performances of the super twisted nematic liquid crystal display(STN-LCD) on the polyimide(PI) surface using polymer film. The NLC pretilt angles generated are about $18^{\circ}$ by the rubbing alignment method on thin plastic substrates. However, the pretilt angle are at about $13^{\circ}$ lower on the glass substrate than on thin plastic substrate. Monodomain alignment of the plastic STN-LCD can be observed. A stable voltage-transmittance(V-T) curve of the plastic STN-LCD was observed on the polyimide(PI) surfaces using polymer film. Also, a faster response time for the plastic STN-LCD on the polyimide(PI) surfaces using polymer film can be achieved.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.12
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• pp.1023-1026
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• 2001

The control of high pretilt angle for nematic liquid crystal (NLC) with negative dielectric anisotropy on the rubbed blending polyimide (PI) of homeotropic and homogeneous alignment surface was studied. High LC pretilt angle on the rubbing blending polyimide of homeotropic PI and SE-7492 surface was measured and the LC pretilt angle increased wish blending ratio and rubbing strength. However, the low LC pretilt angle on the rubbed blending polyimide of homeotropic PI and SE-150 surface was measured. The high pretilt angle of NLC can be achieved by using the blending PI surface.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.10
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• pp.1095-1099
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• 2004

We investigated the electro-optica](EO) performances of the super twisted nematic liquid crystal display(STN-LCD) on the polyimide(PI) surface using polymer film. The NLC(Nematic Liquid Crystal) pretilt angles generated are about 18$^{\circ}$by the rubbing alignment method on thin plastic substrates. However, the pretilt angle are at about 13$^{\circ}$ lower on the glass substrate than on thin plastic substrate. Monodomain alignment of the plastic STN-LCD can be observed. A stable voltage-transmittance(V-T) curve of the plastic STN-LCD was observed on the polyimide(PI) surfaces using polymer film. Also, a faster response time for the plastic STN-LCD on the polyimide(PI) surfaces using polymer film can be achieved.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.209-212
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• 2001

Polyimide(PI) films have been considered as the interlayer dielectric materials due to low dielectric constant, low water absorption, high gap-fill and planarization capability. The PI film was etched with using inductively coupled plasma (ICP). The etching characteristics such as etch rate and selectivity were evaluated to gas mixing ratio. High etch rate was 8300$\AA$/min and vertical profile was approximately acquired 90$^{\circ}$ at CF$_4$/(CF$_4$+O$_2$) of 0.2. The selectivies of polyimide to PR and SiO$_2$ were 1.2, 5.9, respectively. The etching profiles of PI films with an aluminum pattern were measured by a scanning electron microscope (SEM). The chemical states on the PI film surface were investigated by x-ray photoelectron spectroscopy (XPS). Radical densities of oxygen and fluorine in different gas mixing ratio of 07CF4 were investigated by optical emission spectrometer (OES).

• Journal of Electrochemical Science and Technology
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• v.6 no.1
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• pp.26-33
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• 2015

In this study, cell performance and thermal stability of lithium-ion cells with a polyimide (PI) separator are investigated. In comparison to conventional polyethylene (PE) separator, the PI separator exhibits distinct advantage in microporous structure, leading to superior reliability of the cell. The cells with PI separator exhibit good cell performances as same as the cells with PE separator, but their reliability was superior to the cell with PE separator. Especially in the hot-box test at 150 and 180℃, PI separator showed a contraction percentage close to 0% at 150℃, while the PE separator showed a contraction percentage greater than 10% in both width and length. Therefore, the PI separator can be the promising candidate for separators of the next generation of lithium-ion battery.

• Polymer(Korea)
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• v.26 no.4
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• pp.431-438
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• 2002

We studied the orientation behavior and thermal stability of polyimide (PI) molecules under irradiation of polarized UV (PUV) using polarized fourier transform infrared (FTIR) spectroscopy. In the case of PUV-exposed PI films, the remaining PI molecules after photo-degradation showed molecular orientation perpendicular to the irradiated PUV polarization direction predominantly, due to the preferential degradation of PI molecules parallel to the irradiated PUV Polarization direction. On the other hand, the rubbing of PI films induced reorientation of the PI molecules parallel to the rubbing direction. We also investigated the thermal stability of the alignment layers furled by rubbing and PUV irradiation on the PI films using Polarized FTIR. The thermal stability of the PUV irradiated PI alignment layer is lower than that of the rubbed PI layer due to the fragmentation reaction of the PI by PUV.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.209-212
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• 2001

Polyimide(PI) films have been considered as the interlayer dielectric materials due to low dielectric constant, low water absorption, high gap-fill and planarization capability. The PI mm Was etched with using inductively coupled plasma (ICP). The etching characteristics such as etch rate and selectivity were evaluated to gas mixing ratio. High etch rate was $8300{\AA}/min$ and vertical profile was approximately acquired $90^{\circ}$ at $CF_{4}/(CF_{4}+O_{2})$ of 0.2. The selectivies of polyimide to PR and $SiO_{2}$ were 1.2, 5.9, respectively. The etching profiles of PI films with an aluminum pattern were measured by a scanning electron microscope (SEM). The chemical states on the PI film surface were investigated by x-ray photoelectron spectroscopy (XPS). Radical densities of oxygen and fluorine in different gas mixing ratio of $O_{2}/CF_{4}$ were investigated by optical emission spectrometer (OES).