• Journal of the Korean Society of Clothing and Textiles
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• v.45 no.4
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• pp.674-684
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• 2021

Recent advances in electronic technology have engendered a need for research on the use of smart materials in clothing. Electro-conductive fibers are expected to be a crucial element of wearable devices. Therefore, in this study, we have attempted to develop electro-conductive threads and cables using silver nanowires. Based on the characteristics of silver nanowire, in which electro-conductivity can be imparted via heat treatment, we prepared conductive threads by coating nylon yarn with silver nanowires and curing at temperatures of 140℃, 150℃, and 160℃. Conductive threads cured at 140℃ had the highest conductivity, followed by threads cured at 160℃ and 150℃ respectively. The order of the electrical conductivity of the threads after tensile testing was consistent with the original order of the conductivity of the threads. When we evaluated the sensing performance of electro-conductive cables fabricated from these threads, the cables manufactured from threads cured at 140℃ and 160℃ were found to function normally within temperature and humidity sensors. All the cables operated normally in illuminance and electrocardiogram sensors. Thus, we believe that threads made of silver nanowire have sufficient electrical conductivity to be utilized as wearable sensors.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.1
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• pp.51-54
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• 2015

An electro-plating technology on a cured isotropic conductive pattern with a hybrid Cu paste composed of resin matrix, copper, and solder powders has been developed. In a conventional technology, Ag paste was used to perform a conductive pattern on a PCB or silicon substrate. From previous research, the electrical conductive mechanism and principle of the hybrid Cu paste were concisely investigated. The isotropic conductive pattern on the PCB substrate was performed using screen-printing technology. The optimum electro-plating condition was experimentally determined by processing parameters such as the metal content of the hybrid Cu paste, applied current density, and time for the electroplating in the plating bath. The surfaces and cross-sections were observed using optical and SEM photographs. In conclusion, the optimized processing conditions for Cu electro-plating technology on the conductive pattern were a current density of $40mA/cm^2$ and a plating time of 20min on the hybrid Cu paste with a metal content of 44 vol.%. More details of the mechanical properties and processing conditions will be investigated in further research.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.623-624
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• 2013

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.9 s.102
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• pp.1077-1083
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• 2005

Electro-Active Paper (EAPap) is one of attractive electro-active polymer (EAP) materials for artificial muscles due to its many advantages such as light weight, biologically degradable, low cost, large displacement output, low actuation voltage and low power consumption. However, drawbacks of EAPap actuators include low force output and humidity dependence. To enhance the performance of EAPap, conductive polymer (PPy) and SWNT/conductive polymer (PANI) are coated on EAPap PPy as conductive polymer is coated on cellulose EAPap by means of electrochemical deposition. Two different dopants are used in PPy through conducting polymer processing. SWNTS are mixed with PANI in emeraldine base along with different dopants. The compound materials are coated on cellulose EAPap using spin coating system. The performance of PPy/EAPap and SWNT/PANI/EAPap are evaluated in terms of bending displacement, blocked force, and the effects of dopants, humidity, coaling time, voltage and frequency are investigated. Comparing with EAPap actuators, SWNT/PANI/EAPap actuators show $200\%$ improvement of bending displacement and $300\%$ increment of blocked force.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.6
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• pp.96-102
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• 2000

The finishing process for dies and molds is an important process because it has influence on final quality of products. And it is difficult to automatize finishing process so that the process has depended on expert's skill until now. However, recently a study on development of die automatic finishing machine has been progressed, and actually this machine is applied to fabrication of die. But the research about tooling system is not enough and finishing tool must have high machining efficiency and adaptability of curved surface. So, this study investigated the application of conductive elastic tool which is composed of metal-resin bonded pellet and elastic backing material. The metal-resin bonded pellet is used to finish the surface by conventional mechanical grinding or electro-chemial grinding method. And elastic backing material is used to follow the curved surface. So conductive elastic tool has long lifetime, uniform removal rate and adaptability of curved surface.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.275-278
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• 2004

Electro-Active Paper (EAPap) is attractive for EAP actuator due to its merit in terms of light weight, dry condition, large displacement output, low actuation voltage and low power consumption. The EAPap is based on cellulose paper, and is shown to involve primarily transport of ions in response to an external electric field. This actuating mechanism is similar to conductive polymer based actuators. For performance improvement of EAPap, hybrid actuators are tried. The actuators based on cellulose paper attached conducting polypyrrole, polyaniline and single wall carbon nanotube/polyaniline(emeraldine base) have been achieved by Electro chemical deposition and mechanical deposition of the polymers onto cellulose paper.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.12
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• pp.1310-1316
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• 2008

Bi-layer and tri-layer structures of electro-active paper(EAPap) using conductive polyaniline(PANI) coating were investigated to improve bending displacement of cellulose EAPap. Two different counter ions, perchlorate($CIO_4^-$) and tetrafluoroborate($BF_4^-$), are used as dopant ions in the PANI processing. The actuation performances of hi-layer and tri-layer structure are evaluated in terms of tip displacement, blocked force, strain energy density and power output density. The actuation performance of the tri-layer actuator was better than the hi-layer structure, and the maximum displacement and blocked force of tri-layer $CIO_4^-$ doped-PANI-EAPap were 13.2 mm and 0.15 mN, respectively. Also the power output of the actuator is similar to the required power of biological muscle application.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.05a
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• pp.258-262
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• 2001

The contact resistivity was correlated with IFSS and microfailure modes in conductive fiber/cement composites electro-pullout and AE. As IFSS increased, the number of AE signals increased and the contact resistivity increased latter to the infinity. In dual matrix composite (DMC) test and AE, the number of signals with high amplitude and energy in g]ass fiber composite is significantly larger than that of no-fiber composite. Many vertical and diagonal cracks were observed in glass fiber and no-fiber composite under tensile test, respectively. Electro-micromechanical technique and AE can be used efficiently for sensitive nondestructive (NDT) evaluation and to detect microfailure mechanisms in various conductive fibers reinforced brittle and nontransparent cement composites.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.709-712
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• 2002

For the electro-discharge machining of an electro-conductive anisotropic composite, an unsteady state formulation was established and solved by Galerkin's finite element method. The distribution of temperature on work piece, the shape of the crater and the material removal rate were obtained in terms of the process parameters. As the spark was initiated the workpiece immediately started to melt and the heat affected zone was formed. The moving boundary of the crater was also identified with time. When the radial and axial conductivities were increased separately the temperature distribution and the shape of the crater were shifted in the same direction respectively and the material removal rate was found to be higher in the case of increasing radial conductivity rather than the axial conductivity.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.11
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• pp.1008-1013
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• 2003

We have studied the effect of black matrix (BM) according to the dielectric anisotropy of liquid crystals (LCs) for a homogeneously aligned LC cell driven by fringe-electric field. The results show that for a LC with positive dielectric anisotropy (+LC) there is a large transmittance change when using a conductive BM, whereas the transmittance change is low for a LC with negative dielectric anisotropy (-LC). The conductive BM existing on top substrate produces vertical electric field, which makes the LC molecules be tilt upward from the substrate and have small twist angle for the +LC. However, for the -LC the conductive BM affects the LC distribution only slightly due to characteristic of the -LC orienting perpendicular to the field. Therefore, for the +LC the electro-optic characteristics are strongly dependent on conductivity of the BM on top substrate in a homogeneous liquid crystal cell driven by fringe-electric field.