• 폴리머
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• 제31권6호
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• pp.543-549
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• 2007

폴리우레탄의 우수한 기계적 물성에 전기 전도성을 가질 수 있도록 은 입자와의 복합체를 제조하였다. 균일하고 우수한 물성을 나타내기 위해서는 고른 분산성이 중요하게 되는데 폴리우레탄의 hard segment와 soft segment를 바꿔가며 가장 열적 안정성이 뛰어나고 은 입자를 균일하게 분산시킬 수 있는 폴리우레탄의 구조를 파악하였다. 열적 안정성은 방향족 증가와 사슬의 hard segment 비율 증가에 따라 높아짐을 알 수 있었고 분산성에서는 hard segment의 방향족이 포함된 것이 지방족보다 우수한 분산성을 가졌다. 또한 soft segment에 따라서는 낮은 분자량에서 사슬의 motility로 인해 좋은 분산성을 나타내었다. 하지만 전기 전도성에서는 고른 분산성보다도 입자간의 inter-connection을 이룰 수 있는 형태가 가장 낮은 저항값을 나타내었으며. NDI와 낮은 분자량의 PEG로 이루처진 복합체가 가장 좋은 물성을 나타내었다.

• 한국재료학회지
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• 제18권9호
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• pp.503-506
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• 2008

The effect of silver nanoparticles (NPs) incorporation on the electronic properties of poly (3, 4-ethylenedioxythiphene) : poly(styrenesulfonate) (PEDOT : PSS) films was investigated. The surface of silver NPs was stabilized with trisodium citrate to control the size of silver NPs and prevent their aggregation. We obtained ca. 5 nm sized silver NPs and dispersed NPs in PEDOT : PSS solution. Sheet resistance, surface morphology, bonding state, and work function values of the PEDOT : PSS films were modified by silver NPs incorporation as well as annealing temperature. Sodium in silver NPs solution could lead to a decrease of work function of PEDOT : PSS; however, large content of silver NPs have an effect on the increase in work function, resulting from charge localization on the silver NPs and a decrease in the number of charge-trapping-related defects by chemical bond formation.

• 전기학회논문지
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• 제59권12호
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• pp.2250-2255
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• 2010

An fine silver particle has a variety of uses, such as in killing micrograms and as catalysts. Many techniques have been used for the production of the fine particles. Faraday cell, consisting of two silver electrodes in an electrolyte, is unique, but it is hard to get a very fine particle by this method. A finer silver nano-particle producing cell, utilizing a dielectric bed as a lower electric current and higher field controlling means, has been proposed and investigated. The I-V characteristics of the cell and effect of the dielectric bed on the producing finer silver nano-particles have been investigated. The I-V characteristics of the cell with the dielectric bed were different from that of the same system without the bed, due to the increased cell resistance and elevated electric field intensity. It is found that the proposed cell with the dielectric bed can produce finer silver nano-particles effectively, which, however, can be used as one of effective fine silver nano-particle producing means.

• Advances in materials Research
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• 제2권3호
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• pp.133-140
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• 2013

This paper aims to focus on the microwave processing of thick films which is a fast, cheap technique and could be the alternative to the currently used conventional high temperature processing technique. Microwave processing has gained worldwide acceptance as a novel method for heating and sintering a variety of materials, as it offers specific advantages in terms of speed, energy efficiency, process simplicity, finer microstructures and lower environmental hazards. Silver conducting thick films were prepared and processed in the household microwave oven. The films sintered at different time period by keeping the other parameter such as microwave power, film thickness etc constant. The microstructure analysis revealed that the surface morphology of the microwave processed films become compact with respect to the processing time. The sheet resistance for microwave sintered silver films is in the range of 0.003 to $1.207{\Omega}/{\Box}$ where as the films fired at 750 and $850^{\circ}C$ showed the resistance of 0.009 and $0.003{\Omega}/{\Box}$ which can be comparable. The results revealed that the microstructure of the microwave sintered films has more uniform and compact surface than that of the conventionally fired films. The paper reports upon the preparation of silver thick film by screen printing technique and processing the same by microwave which also compared with the conventionally processed thick films.

• 한국운동역학회지
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• 제31권3호
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• pp.183-188
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• 2021

Objective: The purpose of this study was to develop a stretchable joint motion sensor that is based on silver nano-particle. Through this sensor, it can be utilized as an equipment for rehabilitation and analyze joint movement. Method: In this study, precursor solution was created, after that, nozel printer (Musashi, Image master 350PC) was used to print on a circuit board. Sourcemeter (Keithley, Keithley-2450) was used in order to evaluate changes of electric resistance as the sensor stretches. In addition, the sensor was attached on center of a knee joint to 2 male adults, and performed knee flexion-extension in order to evaluate accurate analysis; 3 infrared cameras (100 Hz, Motion Master 100, Visol Inc., Korea) were also used to analyze three dimensional movement. Descriptive statistics were suggested for comparing each accuracy of measurement variables of joint motions with the sensor and 3D motions. Results: The change of electric resistance of the sensor indicated multiple of 30 times from initial value in 50% of elongation and the value of electric resistance were distinctively classified by following 10%, 20%, 30%, 40% of elongation respectively. Through using the sensor and 3D camera to analyze movement variable, it showed a resistance of 99% in a knee joint extension, whereas, it indicated about 80% in flexion phase. Conclusion: In this research, the stretchable joint motion sensor was created based on silver nanoparticle that has high conductivity. If the sensor stretches, the distance between nanoparticles recede which lead gradual disconnection of an electric circuit and to have increment of electric resistance. Through evaluating angle of knee joints with observation of sensor's electric resistance, it showed similar a result and propensity from 3D motion analysis. However, unstable electric resistance of the stretchable sensor was observed when it stretches to maximum length, or went through numerous joint movements. Therefore, the sensor need complement that requires stability when it comes to measuring motions in any condition.

• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2251-2256
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• 2014

We have successfully decorated reduced graphene oxide (RGO) with silver nanoparticles (AgNPs) by microwaving silver alkylcarbamate for 13 seconds using 1-amino-4-methylpiperazine. Uniform AgNPs (20-40 nm) were effectively prepared, and 1-amino-4-methylpiperazine acted as a reaction medium, reducing agent, and stabilizer. Particle size and morphology were correlated with the silver alkylcarbamate concentration and microwave time. The graphene/AgNPs composites were characterized by Raman, X-ray diffraction, and scanning electron microscopy to confirm that the AgNPs were uniformly decorated onto the graphene. Measurements of the transparent conductive property at room temperature indicated that these graphene/AgNPs nanosheets with 55.45% transmittance were electrically continuous with a sheet resistance of approximately $43{\Omega}/{\Box}$.

• 한국대기환경학회지
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• 제16권2호
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• pp.199-208
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• 2000

In this study we investigated on the possibility of platinum and silver catalysts as de-NOx catalyst for activity test of supported metal oxide catalysts. the study was performed with the change of amount of metal and support types. The catalyst was prepared the activity of alumina supported silver catalyst produced by dry and wet impregnation method respectively and the resistance of sulfur for optimum supported silver catalyst,. As a result the activity of alumina supported platinum catalyst was showed at low temperature region but the case of silver catalyst activated at high temperature region. So we finally chose alumina supported silver catalyst as de-NOx target catalyst because alumina supported catalyst showed higher activity than alumina supported platinum catalyst.

• 한국표면공학회지
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• 제53권5호
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• pp.207-212
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• 2020

Silver is an inexpensive precious metal and is used in various jewelry in Asia. Although silver has high potential, it has corrosion resistance that is vulnerable to boiling sulfuric acid and nitric acid. So, silver research is needed to prevent the corrosion with environment. But silver corrosion is not studied. sulfuric acid make the uniform corrosion and chloride ion make the pitting corrosion. ICCP inhibits the corrosion because it offset electrons. This study used a potential from - 4 V to 4 V to check the effect of potential. Corrosion rate is lowet at -1 V.

• Tribology and Lubricants
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• 제14권3호
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• pp.1-6
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• 1998

An experimental study was performed to discover the effect of environmental conditions on the rolling resistance behavior of pure silver and lead coated 52100 bearing steel. Pure silver and lead coatings were produced by a thermal evaporation coating method. Experiments using a thrust ball bearing-typed rolling test-rig were performed under vacuum, dry air and controlled humidity conditions. Results showed that agglomeration of particles were suppressed in vacuum environment and resulted in low and stable rolling resistance by shakedown phenomena. Also, humidity related closely to the agglomeration of particles and the rolling resistance after the failure of coated layer.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제27회 춘계학술대회
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• pp.47-54
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• 1998

An experimental study was performed to discover the effect of environmental conditions on the rolling resistance behavior of pure silver and lead coated 52100 bearing steel. Pure silver and lead coating were produced by a thermal evaporation coating method. Experiments using a thrust ball bearing-typed rolling test-rig were performed under vacuum, dry air and controlled humidity conditions. Results showed that agglomeration of particles were prevented in vacuum environment and as it showed low and stable rolling resistance by shakedown phenomena. Also, humidity relates closely to the agglomeration of particles and increased the rolling resistance after the failure of coated layer.