• Journal of Industrial Convergence
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• v.20 no.12
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• pp.79-85
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• 2022

Recently, a smartphone manufactured on a flexible substrate has been released as an electronic device, and research on a stretchable electronic device is in progress. In this paper, a silicon-based stretchable material is made and used as a substrate to implement and evaluate an optical sensor device using oxide semiconductor. To this end, a substrate that stretches well at room temperature was made using a silicone-based solution rubber, and the elongation of 350% of the material was confirmed, and optical properties such as reflectivity, transmittance, and absorbance were measured. Next, since the surface of these materials is hydrophobic, oxygen-based plasma surface treatment was performed to clean the surface and change the surface to hydrophilicity. After depositing an AZO-based oxide film with vacuum equipment, an Ag electrode was formed using a cotton swab or a metal mast to complete the photosensor. The optoelectronic device analyzed the change in current according to the voltage when light was irradiated and when it was not, and the photocurrent caused by light was observed. In addition, the effect of the optical sensor according to the folding was additionally tested using a bending machine. In the future, we plan to intensively study folding (bending) and stretching optical devices by forming stretchable semiconductor materials and electrodes on stretchable substrates.

• Journal of the Korean institute of surface engineering
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• v.56 no.2
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• pp.160-168
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• 2023

Recently, investigation on metallization is a key for a stretchable display. Amorphous metal such as Ni and Zr based amorphous metal compounds are introduced for a suitable material with superelastic property under certain stress condition. However, Ni and Zr based amorphous metals have too high resistivity for a display device's interconnectors. In addition, these metals are not suitable for display process chemicals. Therefore, we choose an aluminum based amprhous metal Al-Mo as a interconnector of stretchable display. In this paper, Amorphous Forming Composition Range (AFCR) for Al-Mo alloys are calculated by Midema's model, which is between 0.1 and 0.25 molybdenum, as confirmed by X-ray diffraction (XRD). The elongation tests revealed that amorphous Al-20Mo alloy thin films exhibit superior stretchability compared to pure Al thin films, with significantly less increase in resistivity at a 10% strain. This excellent resistance to hillock formation in the Al20Mo alloy is attributed to the recessed diffusion of aluminum atoms in the amorphous phase, rather than in the crystalline phase, as well as stress distribution and relaxation in the aluminum alloy. Furthermore, according to the AES depth profile analysis, the amorphous Al-Mo alloys are completely compatible with existing etching processes. The alloys exhibit fast etch rates, with a reasonable oxide layer thickness of 10 nm, and there is no diffusion of oxides in the matrix. This compatibility with existing etching processes is an important advantage for the industrial production of stretchable displays.

• The Research Journal of the Costume Culture
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• v.16 no.1
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• pp.48-57
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• 2008

The purpose of this study was to examine the inconvenience when putting on stretchable pants and to analyze the whole actual conditions of making of the lining fabrics. For this study, we conducted a survey of women in their twenties and collected the basic data and master pattern through material of a woman's wear brand and the interview and questionnaires. The results of this study were as follows. First, the survey result for the woman consumers it showed that the most uncomfortable problem about the lining of pants was not sufficient stretch as much as the out-shell. Secondly, it was shown that many brands(46.7%) were using the lining fabrics of stretch clothes mixed with 'non-stretch fabrics' and 'stretch fabrics'. The result of lining pattern making for the stretch pants showed that the ease of the lining fabrics was 0 to 4cm in the hip girth more than out-shell. The ease in crotch width was 0 to 1.3cm for lining fabrics. But in the stretch lining fabrics the ease for front crotch width was 0 to 1cm more than out-shell. The lengths of crotch rising were -0.7 to 1.3cm for the non-stretch lining fabrics and -1 to 1cm for the stretch lining fabrics.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.3
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• pp.49-54
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• 2020

To attach a stretchable/flexible electrode to something or something to on electrode, conductive adhesives must be stretchable/flexible to suit the properties of the electrode. In particular, conductive adhesive require durability and heat resistance, and unlike conventional adhesives, they should also have conductivity. To this end, Epoxy, which has good strength and adhesion, was selected as an adhesive, and a plasticizer and a reinforcement were mixed instead of a two-liquid material consisting of a conventional theme and a hardener, and a four-liquid material was used to give stretchability/flexibility to high molecules. The conductive filler was selected as silver, a material with low resistance, and for high conductivity, three shapes of Ag particles were used to increase packing density. Conductivity was compared with these developed conductive adhesives and two epoxy-based conductive adhesives being sold in practice, and about 10 times better conductivity results were obtained than products being actually sold. In addition, conductivity, mechanical properties, adhesion and strength were evaluated according to the presence of plasticizers and reinforcement agent. There was also no problem with 60% tensile after 5 minutes of curing at 120℃, and pencil hardness was excellently measured at 6H. As a result of checking the adhesion of electrodes through 3M tape test, all of them showed excellent results regardless of the mixing ratio of binders. After attaching the Cu sheet on top of the electrode through conductive adhesive, the contact resistance was checked and showed excellent performance with 0.3 Ω.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.60-60
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• 2010

최근 사람의 피부나 내부 장기처럼 수축과 팽창이 일어나는 부위 등에 이식 가능한 소자 개발에 대한 연구가 많이 보고되었다. 현재 이런 stretchable electronics에 대한 연구는 channel material로서 실리콘이나 유기물, 그리고, 광학 리소그래피가 가능한 micro-electronics 에 국한되어 있다. 우리는 CVD 로 성장된 수십 나노미터의 직경을 갖는 $SnO_2$ 나노선을 슬라이딩 전이하여 실리콘 웨이퍼 상에서 소자화하고 이를 스트레칭이 가능한 PDMS 기판에 전이하여 stretchable nanowire device를 구현하였다. 해당 소자는 윗면과 아랫면 모두 폴리머로 덮여 있고 측정을 위한 전극이 따로 구성되어 있어 소자 특성의 열화가 최소화되게 제작되었으며, 수축과 팽창 시 받는 스트레인 또한 최소화하는 mechanical neutral structure를 갖게 제작되었다. 또한, 소자와 소자 혹은 소자와 전극간의 연결을 S자 형태로 구성하여 기판으로 사용된 PDMS를 수십 % 스트레칭하여도 소자의 전기적 특성이 유지되는 것을 확인하였다. 이처럼 스트레칭이 가능한 나노선 소자는 구김이나 잡아 늘여지게 되는 다양한 표면위에 간단하게는 논리회로뿐만 아니라 나노선의 장점을 이용한 다양한 센서 및 기능 소자로서 응용이 가능할 것으로 예상된다.

• Journal of the Korean Society of Costume
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• v.58 no.4
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• pp.99-112
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• 2008

The aim of the study was to look into the construction methods of historical corsetry and compare them with the construction methods of corsetry today. Through a comparative study, it was concluded that the design, material, sewing and functions of corsetry of a certain period are sum of the clothing techniques and fashion of the time. Corset was first appeared at the end of the 16th century. It has been through many changes in terms of items, materials, patterns, sewing methods in order to make right silhouettes of the time. Now corsetry has been developed into various items such as waist nipper, all-in-one, nipper bra, and girdle. All these items have a common purpose, that is to improve the body shape. The corsetry of the past was made of non stretchable materials, so they used to restrict body movements, and required individual fitting several times. Due to the development of thin durable stretchable fabrics, functional bones, and advanced sewing machines, construction methods of seam, hem and opening are simplified compare to their predecessors. Consequently corsetry became less weighted, easy to wear, easy to wash and easy to mass produce. Yet they have consistency in sewing techniques such as using bones or wires to support bodice shape, using durable twill fabrics over plain for attractive body shapes.

• The Research Journal of the Costume Culture
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• v.16 no.4
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• pp.609-618
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• 2008

The purpose of this study is to examine the inconvenience when putting on stretch pants and to compare and analyze the pattern making method of pants made of the stretch and non-stretch fabric to develop functional and good looking stretch pants. For this study, we conducted a survey of women in their twenties and collected the basic data and master pattern through material of a woman's wear brand and the interview and questionnaires. The results of this study are as follows. First, the survey result for the woman consumers showed that pants were estimated as the most uncomfortable item among the stretch clothes and when they put the stretch pants on, the most uncomfortable parts of out-shell were the hip girth and rise. Secondly, the result of pattern making method of the pants was as follows. The ease of the stretch pants pattern was 0cm in the waist girth and -1 to -1.5cm in the hip girth more than non-stretch pants. The ease in crotch, inseam and outseam length was 0cm for both.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.4
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• pp.77-82
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• 2014

Stretchable electrodes are focused due to many demands for soft electronics. One of the candidates, carbon black composites have advantages of low cost, easy processing and decreasing resistivity in a certain range during stretching. However, the electrical conductivity of carbon black composites is not enough for electronic devices. Graphene is 2-dimensional nanostructured carbon based material which shows good electrical properties and flexibility. They may help to improve electrical conductivity of the carbon black composites. In this study, graphene was added to a carbon black electrode to enhance electrical properties and investigated. Electrical resistivity of graphene added carbon electrode decreased comparing with that of carbon black electrode because graphene bridged non-contacting carbon black aggregates to strengthen the conductive network. Also graphene reduced an increase in the resistance of the carbon black electrode applied to strain because they connected gap of separated carbon black aggregates and aligned along the stretching direction at the same time. In conclusion, an addition of graphene to carbon black gives two benefits on the electrical properties of carbon black composite as a stretchable electrode.

• Journal of Fashion Business
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• v.21 no.6
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• pp.16-30
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• 2017

Currently, e-textile market is rapidly expanding and the emerging area of e-textiles requires electrically conductive threads for diverse applications, including wearable innovative e-textiles that can transmit/receive and display data with a variety of functions. This study introduces hybrid nano-structures which may help increase the conductivity of the textile threads for use in wearable and flexible smart apparels. For this aim, Ag was selected as a conductive material, and yarn treatment was implemented where silver nanowire (AgNW) and graphene flake (GF) hybrid structures overcome the limitations of the AgNW alone. The yarn treatment includes several treatment conditions, e.g., annealing temperature, annealing time, binder material such as polyurethane (PU), coating time, in order to search for the optimum method to form stable conductive nano-scale composite materials as thin film on the surface of textile yarns. Treatedyarns showed improved electrical resistance readings. The functionality of the spandex yarn as a stretchable conductive thread was also demonstrated. When the yarn specimens were treated with colloid of AgNW/GF, relatively good electrical conductivity value was obtained. During the extension and recovery cycles of the treated yarns, the initial resistance values did not deteriorate significantly, since the network of nanowire structure with the support of GF and polyurethane stayed flexible and stable. Through this research, it was found that when one-dimensional structure of AgNW and two-dimensional structure of GF were mixed as colloids and treated on the surface of textile yarns, flexible and stretchable electrical conductor could be formed.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.67-67
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• 2012

Graphene, two-dimensional one-atom-thick planar sheet of carbon atoms densely packed in a honeycomb crystal lattice, exhibits fascinating electrical properties, such as a linear energy dispersion relation and high mobility in addition to a wide-range optical absorption and high thermal conductivity. Graphene's outstanding tensile strength allows graphene-based electronic and photonic devices to be flexible, bendable, or even stretchable. Recently many groups have reported high performance electronic and optoelectronic devices based on graphene materials, i.e. field-effect transistors, gas sensors, nonvolatile memory devices, and plasmonic waveguides, in which versatile properties of graphene materials have been incorporated into a flexible electronic or optoelectronic platform. However, there are several fundamental or technological hurdles to be overcome in real applications of graphene in electronics and optoelectronics. In this tutorial we will present a short introduction to the basic material properties and recent progresses in applications of graphene to electronics and optoelectronics and discuss future outlook of graphene-based devices.