• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.284-284
• /
• 2011

Recently, the increasing degree of device integration in the fabrication of Si semiconductor devices, etching processes of nano-scale materials and high aspect-ratio (HAR) structures become more important. Due to this reason, etch selectivity control during etching of HAR contact holes and trenches is very important. In this study, The etch selectivity and etch rate of TEOS oxide layer using ACL (amorphous carbon layer) mask are investigated various process parameters in CH2F2/C4F8/O2/Ar plasma during etching TEOS oxide layer using ArF/BARC/SiOx/ACL multilevel resist (MLR) structures. The deformation and etch characteristics of TEOS oxide layer using ACL hard mask was investigated in a dual-frequency superimposed capacitively coupled plasma (DFS-CCP) etcher by different fHF/ fLF combinations by varying the CH2F2/ C4F8 gas flow ratio plasmas. The etch characteristics were measured by on scanning electron microscopy (SEM) And X-ray photoelectron spectroscopy (XPS) analyses and Fourier transform infrared spectroscopy (FT-IR). A process window for very high selective etching of TEOS oxide using ACL mask could be determined by controlling the process parameters and in turn degree of polymerization. Mechanisms for high etch selectivity will discussed in detail.

• Macromolecular Research
• /
• v.16 no.8
• /
• pp.734-740
• /
• 2008

A new crosslinked, poly(acrylic acid)-based, dehydrating agent was synthesized through solution polymerization. The Taguchi method, a robust experimental design, was adopted to optimize the synthetic conditions based on the moisture and water absorbing capacities of the dehydrating agent. The method applied for the experiment was a standard L27 ($3^8$) orthogonal array with eight parameters and three levels. By analyzing the variance of the test results, the most effective parameters to control the moisture absorbing capacity (MAC) and its rate were the kind of alkaline base (LiOH, NaOH, or KOH) used as a neutralizing agent of the acrylic acid monomer and the degree of neutralization: The maximum MAC of 40% was achieved at only 2 hat $32^{\circ}C$ and 50% RH when KOH was used as a base and the degree of neutralization was 90%, respectively. However, the water absorbing capacity (WAC) of the resulting dehydrating agent was very low at 158 g/g, indicating that WAC is unaffected by MAC and its rate in this system. The surface morphologies of the agents were examined using scanning electron microscopy (SEM).

• Preventive Nutrition and Food Science
• /
• v.10 no.3
• /
• pp.224-230
• /
• 2005

The effects of low viscosity chitosan on the rheological properties of soymilk using a model system and on tofu qualities were examined. The flow behavior of soy milk with chitosan closed the Newtonian flow and stabilized according to increasing chitosan concentration. The soymilk containing $glucono-\delta-lactone$ exhibited a more pseudoplastic flow behavior compared with that of the control soymilk. The addition of low viscosity chitosan to the tofu preparation did not significantly affect its physicochemical properties. However, the results of the TEM image and instrumental textural properties showed that low viscosity chitosan affected the construction of the tofu structure. Chitosan tofu had low scores across the whole field of appearance in the sensory evaluation, and its overall eating quality was scored significantly lower. These results suggest that the addition of low viscosity chit os an affects the quality of tofu, which changes according to the degree of polymerization and concentration of chitosan.

• Textile Coloration and Finishing
• /
• v.4 no.4
• /
• pp.110-116
• /
• 1992

For the modification of PET surface, Perfluoropropene and Methyl alcohol were LT-plasma polymerized on the PET fabrics as thin films by means of 13.56 MHz radio frequency generator. The surface properties of PET fabrics were modified from hydrophobic to hydrophilic by application of the postplasma reaction of thin films. The evidence of the modification was identified by observation of the presence of hydroxy group in IR spectrum and the evaluation of degree of hydrophilicity was performed by measuring frictional static voltage of PET fabric with cotton fabric. For the case of modification by PFP, the result performed at the condition of 25 W, 70 m torr has shown to be effective, and for MeOH, result performed at the condition of 25 W, 100 m torr effective. The effect of hydrophilic surface modification of MeOH plasma polymer was superior to that of PFP-plasma polymer.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2008.04a
• /
• pp.222-228
• /
• 2008

The chemical composition and thermal, crystal characterization of oak mushroom waste were investigated in comparison with those normal oak wood for utilization of cellulose from oak mushroom waste. The oak mushroom waste contained a higher percentage of ash, and hot water extractives than oak wood. This results indicated that the materials inside the body are easily decomposed during the oak mushroom cultivation. The lower percentage of holocellulose and a-cellulose of oak mushroom waste caused by fungal decomposition too. Whereas, the thermal decomposition behavior and crystallinity of oak mushroom waste was similar to that of normal oak wood, which indicated that the cellulose characterization of oak mushroom waste is resistant to fungal decomposition. In additionally, a degree of polymerization of oak mushroom waste must be investigate for examination of cellulose crystalline characterization, especially.

• Textile Coloration and Finishing
• /
• v.16 no.4
• /
• pp.19-25
• /
• 2004

Both poly(vinyl alcohol)$(PVA)-I_2$ and PVA-dye polarizing film were prepared using PVA with number-average degree of polymerization of 1,700, 2,300, 2,600. The optical property of used dye in this study closed to the that of iodine. The PVA-dye polarizing film was prepared through the dyeing process. In comparison of the result of the measurement of the heat and humidity resistance of two types polarizing films, it of PVA-dye polarizing film was higher than that of a conventional $PVA-I_2$polarizing film. The transmittance and the polarization efficiency of PVA-dye polarizing film was significantly influenced by dye concentration, dipping time, salt concentration, and temperature of dye bath. The PVA-dye polarizing film exhibited a high polarization efficiency of 99.3% and a good transmittance of 42.4%.

• Journal of the Korean Applied Science and Technology
• /
• v.5 no.1
• /
• pp.53-62
• /
• 1988

Properties of aqueous solution, that is, the viscosities and solubilities of benzene were observed in relation to critical micelle concentration of each alkyl aldehyde polyoxyethylene glycol acetal type surfactant. These showed that the mininum points in specific viscosity/concentration-concentration curves were corresponded with the critical micelle concentration obtained by surface tension and appeared the remarkable increase of non-Newtonics according to the increase of the number of carbon in hydrophobic groups. The fluidity of non-Newtonics is not observed by a little increase of the degree of polymerization in polyoxyethylene glycol groups.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.2
• /
• pp.407-414
• /
• 2014

Polyacrylonitrile (PAN) copolymers with different methyl acrylate (MA) contents were synthesized via solution polymerization and used as precursors for high-performance PAN ultrafine fibrids. The chemical structures of the copolymers were characterized using Fourier-transform infrared spectroscopy and $^{13}C$ nuclear magnetic resonance spectroscopy. Their particle sizes and aspect ratios increased with increasing viscosity, and the degree of crystallinity increased with decreasing concentration of copolymer solution. In contrast, their peak temperature and heat of exotherm increased with decreasing concentration of the copolymer solution. The aromatization indices (AIs) of the fibrids increased with increasing heat-treatment time; however, the AIs decreased when the heat-treatment temperature was higher than the onset temperature of the copolymers. On the other hand, the crystal sizes of the fibrids decreased with increasing concentration of the copolymer solution when the MA content was held constant.

• Journal of the Korean Chemical Society
• /
• v.12 no.3
• /
• pp.114-120
• /
• 1968

Fe-EDTA complex, which is easily formed when Fe salt and EDTA.2Na are mixed in the aqueous medium, is found to be a very effective catalyst in the dehydropolycondensation of aminophenols. In the dehydropolycondensation of aminophenols, the catalyst, Fe(Ⅲ)-EDTA complex (higher oxidation state) is reduced to less stable Fe(Ⅱ)-EDTA complex (lower oxidation state), and the latter is easily oxidized by air to the original higher oxidation state complex, therefore the catalytic action of Fe-EDTA complex is found to be recycled effectively. Under the catalytic action of the above mentioned complex, p-aminophenol is polymerized in the aqueous medium to form the oligomers of p-aminophenol, which the degree of polymerization to be 5 or more. The oligomers formed contain partly quinone nucleus as well as amino and hydroxyl groups. In this study, the effects of the solvents and characteristics of the oligomers are discussed. These types of polymerizations catalyzed by the metallic chelate compounds are considered to be very closely related to the reactions in the living matters.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.263.2-263.2
• /
• 2013

We report a systematic investigation of a set of macrophotoinitiators for use in polymerization-based signal amplification. To test the dependence of photopolymerization responses on the number of photoinitiators localized per molecular recognition event, we gradually increased the number of photoinitiator molecules coupled to a scaffold macromolecule. Macrophotoinitiators constructed with an average of 7 to 168 photoinitiators per polymer with the goals of quantifying the relationship between the number of initiators per binding event and the degree of amplified colorimetric readout. To evaluate the capacity of the macrophotoinitiators to detect molecular recognition, neutravidin was coupled to these molecules to recognize biotin-labeled DNA immobilized on biochip test surfaces. Fluorescein macroinitiators are found to be useful in detecting molecular recognition above a threshold of initiators per polymer. Above this threshold, increasing the number of initiators per macroinitiator resulted in increased signal strength.