• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.5
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• pp.709-715
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• 1990

SiO2 films were nitrided by tungsten-halogen heated rapid thermal annealing in ammonia gas at temperatures of 900-1100\ulcorner for 15-180sec. The nitroxide films were analyzed using Auger electron spectroscopy. MIS caapcitors were fabricated using these films as gate insulators. I-V and C-V characteristics of MIS capacitors were investigated. The AES depth profiles of nitroxide film show that the nitrogen rich layer is, at the early stage of nitridation, formed at the surface of nitroxide film and near the interface between nitroxide and silicon. Nitridation of SiO2 makes the film have a larger effective average refractive index. The thermal nitridation of SiO2 on silicon causes the flatband voltage shift due to the change of the fixed charge density. It is found that the dominant conduction mechanism in nitroxide is Fowler-Nordheim tunneling. Rapid thermal nitridation of 200\ulcornerSiO2 on silicon results in an improvement in the dielectric breakdown electric field.

• Macromolecular Research
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• v.13 no.3
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• pp.229-235
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• 2005

Various alkoxyamine initiators for nitroxide mediated radical polymerization (NMRP) were prepared in high yields by a simple substitution reaction of nitroxide anions with benzyl bromide. The required nitroxide anions were easily generated by treating either nitroxide free radicals or hydroxy amine with an alkali metal such as sodium or potassium in THF. This method is both practical and efficient, since the ionic conditions prevent other side reactions from occurring, such as the self-coupling or oligomerization reactions that are observed in the case of radical trapping conditions. To demonstrate the utility of the resulting alkoxyamine initiators, end- and telechelic-alkoxyamine PEG macroinitiators derived from the alkoxyamines were synthesized by a simple chemical modification, and used for the preparation of PEG-b-PS and PS-b-PEG-b-PS block copolymers by NMRP.

• Elastomers and Composites
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• v.44 no.1
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• pp.55-62
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• 2009

In this study, investigation on the polymerization characteristics of isoprene through nitroxide mediated controlled/"living" radical polymerization techniques was attempted. In the presence of acetol, linear increase of isoprene conversion with time and low polydispersities of the resulting polymers ($M_w/M_n$ < 1.5) were observed, which suggest successful controlled/"living" radical polymerization of isoprene. The microstructure of the resulting polyisoprene was composed of $\sim$ 22% of 3, 4, $\sim$30% of 1, 4-cis and $\sim$ 48% of 1, 4-trans. The optimum polymerization temperature was 145 $^{circ}C$, below which no significant polymerization behavior was observed. Non-cyclic nitroxide, such as di-tert-butyl nitroxide (DTBN) could not mediate the polymerization, whereas cyclic nitroxides (2, 2, 6, 6-tetramethyl-1-peperidine 1-oxyl (TEMPO) and 4-oxo-2, 2, 6, 6-tetramethyl-1-peperidine 1-oxyl (oxoTEMPO)) were successfully employed for the polymerization. However, isoprene dimerization reaction through Diels-Alder process was also observed at the given polymerization condition, which afforded a significant amount of limonene. Isoprene thermal autoinitiation was also possible, which was, however, considered to be not significant under the given polymerization condition.

• Electrical & Electronic Materials
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• v.3 no.2
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• pp.105-114
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• 1990

SiO$_{2}$막을 NH$_{3}$분위기에서 급속열처리 하여 nitroxide막을 생성시키고 그 전기적 특성을 조사하였다. 굴절율과 유전율은 열처리시간과 온도에 따라 증가 하였으며 IR스펙트럼분석으로 SiO$_{2}$박이 질화된 것을 확인하였다. 절연파괴내력은 대체로 SiO$_{2}$막보다 우수하였으며 .+-.BT 처리와 C-V측정의 결과 nitroxide막이 초기 산화막보다 고전계 stress에 대해 안정한 특성이 나타났다. MIS 다이오드의 1/f 잡음 특성은 C-V 측정결과와 비슷한 경향을 나타내어 1/f 잡음특성이 박막의 계면특성과 밀접한 관련성이 있음을 알 수 있었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1988.05a
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• pp.78-81
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• 1988

Nitroxide films were made from the $NH_3$ gas nitridation of as-grown $SiO_2$. The electrical characterization results including C-V characteristics and BT stress generally indicate that the high field stress instability and insulator-substrate interfacial characteristics are improved by nitridation of $SiO_2$. A C-V technique was used to determine the surface state density $N_{55}$ and then $N_{55}$ in the nitroxide-substrate interface was $8{\times}10(/eVcm^2$). This $N_{55}$ is related with 1/f noise was revealed experimentally and relationship was plotted and 1/f noise characteristics were also improved by nitridation of of $SiO_2$By the results of measurements on these films show that very thin thermal silicon nitroxide films can be used as gate dielectrics for future highly scaled-down VLSI device.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.62-62
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• 2006

Based on the redox couples of a nitroxide radical, organic radical polymers were utilized as the electrode-active or charge-storage component for a secondary battery. We call a battery composed of the radical polymer electrode as "organic radical battery". Organic radical battery has several advantages: high capacity, high power-rate performance, long cycle ability, and environmentally-benign features. Synthesis and electrochemical studies of nitroxide polymers are described. Battery fabrication and cell performance are also reported.

• Macromolecular Research
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• v.15 no.4
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• pp.324-329
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• 2007

An octa-functional alkoxyamine initiator, with the 2,2,6,6-tetramethyl-l-piperidinyloxy (TEMPO) free radical, was synthesized based on resorcinarene, with its efficiency to initiate the nitroxide-mediated free radical copolymerization of styrene and methyl methacrylate (MMA) described. A difunctional analogue of this initiator was also synthesized, using resorcinol as the core molecule. The structures of the resulting initiators were confirmed by homolysis studies based on electron spin resonance spectroscopy and molecular modeling. The polymerization behavior and characteristics of the polymers obtained using these two initiators were also compared. Well-defined star-shaped and linear random copolymers, with low polydispersities and controlled molecular weights, were prepared. The efficiencies of these initiators towards copolymerization, as well as the parameters permitting the formation of well-defined polymers, were also investigated. The reactivity ratios were $r_a=0.42(a=styrene)\;and\;r_b=0.33(b=MMA)$ for the octa-functional initiator system and $r_a=0.45\;and\;r_b=0.39$ for the difunctional initiator system.

• Polymer(Korea)
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• v.34 no.6
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• pp.553-559
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• 2010

The paper describes the preparation and characterization of conductive polyaniline-modified polymers by growing of aniline onto functionalized poly(styrene-co-p-methylstyrene) [P(St-co-MSt)]. For this purpose, P(St-co-MSt) was synthesized via nitroxide mediated radical polymerization (NMRP) and then N-boromosuccinimide was used for introduction of bromine to the benzylic positions of copolymer. Afterwards, 1,4-phenylenediamine was linked to the brominated P(St-co-MSt) and functionalized copolymer $[P(St-co-MSt)-NH_2]$ was prepared. The graft copolymerization of aniline monomers onto functionalized P(St-co-MSt) was initiated by oxidized phenylamine groups after addition of ammonium peroxydisulfate (APS), and p-toluenesulfonic acid-doped PANI was chemically grafted onto P(St-co-MSt) via oxidation polymerization. The obtained terpolymer was studied by FTIR and UV-Vis spectroscopy and its thermal behaviour were examined by DSC and TGA analyses. The conductivity of terpolymer was measured by four-point probe method and electroactivity was measured by cyclic voltammetry (CV). The solubility of P(St-co-MSt)-g-PANI was examined in common organic solvents.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.337-337
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• 2006

The synthesis of an octafunctional resorcinarene based initiator for nitroxide mediated polymerization and its ability to yield random star copolymers of styrene and methyl methacrylate is studied. The effect of the initiator conformations towards its activity and the conditions that permit the formation of well-defined star block copolymers is also investigated in detail. The characterization of the initiator and the polymers were carried out by various spectro-analytical techniques. Well-defined random copolymers were obtained with controlled molecular weight and low PDI depending on the monomer feed.

• Proceedings of the Korean Fiber Society Conference
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• 1990.06b
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• pp.67-67
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• 1990

Three non-ionic and two anioinic spin probes, differing in size and substituent, were synthesized. Their mobility in dried nylon 6 film was investicated by the spin probe technique using electron spin resonance spectrometer. When the size of a spin probe was large and the interaction between the probe molecules and polymer chains existed, the mobility of spin probes decreased. From Arrhenius plots of rotational correlation time, one discontinuity point ($T_d$) was determined. The activation energies for rotation below and above $T_d$ were discussed in terms of the mode of probe rotation. Three spin probes could be viewed as azo dyes having a built-in nitroxide radical. Photolysis of them in dimethylformamide and in nylon 6 film was performed by exposure to 254 nm UV light in the presence of air. It was found that dyes having a built-in nitroxide radical showed better photostability than dyes derived from ${\bata}-naphthol$..