• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.115.2-115.2
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• 2014

2004년에 최초의 2D 물질인 그래핀이 발표된 이후로 그래핀에 대한 관심이 매우 높다. 그래핀은 매우 높은 캐리어 이동도와 높은 광학 투과도, 높은 기계적 강도, 뛰어난 유연성등 다양하고, 뛰어난 물리적, 광학적, 기계적 성질을 갖고 있다. 이러한 뛰어난 성질로 인해 초고속 전자소자, 유연소자, 투명전극, 광학소자등 다양한 분야의 응용이 기대되어, 현재 물리학, 화학, 재료등 여러분야에서 활발히 연구가 진행되고 있다. 이러한 활발한 연구에도 불구하고 그래핀이 가진 기본적인 물리적 특성인 "제로 밴드갭" 특성으로 인해 낮은 소모전력이 요구되는 전자소자와 또한 광학소자로서의 응용에 한계를 보이고 있는 것이 사실이다. 그래핀의 기본적인 물리적 성질인 "제로 밴드갭"에서 탈출해 밴드갭을 증가하기 위해 나노리본, 바이레이어 그래핀등, 다양한 연구가 진행되고 있다. 하지만, 이를 통한 밴드갭의 증가량은 충분히 크지않아서 그래핀의 전자 및 광학적 응용이 아직까지는 매우 어렵다. 이러한 그래핀의 물질적 한계에 비추어 최근에 그래핀과 달리 충분한 밴드갭이 있어 반도체 특성을 가지는 Transition Metal DichalCogenide (TMDC) 물질에 대한 관심이 매우 높다. TMDC물질은 그래핀과 같이 2차원 물질로서 극히 얇으며, 또한 밴드갭을 가지고 있다. 따라서 실리콘과 같이 전자소자, 광학소자의 응용이 더욱 현실적으로 가능하다. 가장 대표적인 물질은 MoS2, WS2등을 들수 있다. TMDC 물질의 연구에서 가장 기본적으로 선행되어야할 연구분야는 바로 물질 성장에 있으며, 본 연구에서는 가장 대표적인 성장방법인 화학기상증착(CVD), 스퍼터링-물리적기상증착 (PVD)를 이용한 MoS2, WS2등의 TMDC의 성장연구에 대해 논의하고자 한다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.12
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• pp.1465-1471
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• 2013

The electrical and mechanical properties of room temperature vulcanized (RTV) silicone rubber composites are investigated as functions of multi-walled carbon nanotube (CNT), carbon black (CB), and thinner content. The thinner is used to improve the CNT and CB dispersion in the matrix. The electrical and mechanical properties of the composite with CNT are improved when compared to the composite with CB at the same content. As the thinner content is 80 phr, the electric resistance of the composite decreases significantly with the CNT content and shows contact point saturation of CNT at 2.5 phr. As the thinner content increases, the dispersion of conductive particles improves; however, the critical CB content increases because of the reduction in the CB weight ratio. It is believed that an electrode that needs good flexibility and excellent electrical properties can be manufactured when the amount of CNT and CB are increased with the thinner content.

• Journal of the Korean Chemical Society
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• v.53 no.3
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• pp.335-339
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• 2009

Polydimethylsiloxane (PDMS) with methacrylate endgroup is used as contact lens material with elasticity and high oxygen permeability. PDMS prepolymer with methacrylate endgroup was prepared by reacting PDMS (polydimethylsiloxane) with HEMA (2-hydroxyethyl methacrylate). The HEMA-substituted PDMS prepolymer was then copolymerized using AIBN (azobisisobutyronitrile) with BMA (butyl methacrylate; to increase elasticity and flexibility). The water content, oxygen permeability, and visible-ray transmissibility of the resulting polymer were measured to be 23%, 83% and Dk/t > 50, indicating that the copolymer can be used as a good contact lens material.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.3 s.151
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• pp.481-486
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• 2006

There are attempts to utilize Hanji for apparel material, but, the reason that the strength and durability of Hanji decrease to a great extent in the wet condition, restricts the usability of Hanji. In order to improve the resistance against water, Hanji was treated with silicone type water repellent agents. The treatment was carried out by conventional pad-dry-cure method. The optimum treatment condition was obtained by varying the concentration of repellent agent, curing temperature and time. Water repellency was tested by spray rating method. Wet and dry tensile strength, tearing resistance and abrasion resistance were examined after the treatment. Flexural stiffness and wrinkle recovery angles of hanji were also measured. In result, the optimum condition of treatment was at resin concentration of 40g/l, catalyst concentration of 20g/l(half of resin concentration), curing temperature of 160$^{circ}C$, curing time of 120 sec. Flexural stiffness of Hanji was hardly increased and wrinkle recovery angle of Hanji was improved a little by resin treatment. After the treatment, in dry condition, tensile strength and tearing resistance were little changed but abrasion resistance was improved. In wet condition, tensile strength, tearing strength and abrasion resistance were improved.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.3
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• pp.259-265
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• 2006

We polymerized material of AA(Acrylic acid) and BMA(butyl methacrylate) to make up for the weak points of hydrogel contact lens. The synthesis process of silicone synthesis is as follows. Acrylate-PDMS(Polydimethylsiloxane)-Urethane prepolymer was composed after Diisocynate reacted with HEMA(2-hydroxyethylmethacrylate) under the catalyst and it reacted again with bis(hydroxyalkyl) terminated poly(dimethylsiloxane) with high oxygen transmissibility characteristics. HEMA(2-hydroxyethylmethacrylate) was used to make prepolymer that can be polymerized and the urethane was used to improve elasticity and oxygen transmissibility, copolymerization was performed with conventional hydrogel contact lens materials to make silicone hydrogel contact lens with higher oxygen transmissibility. For manufacturing of contact lens, We added BMA(Butyl methacrylate) with better elasticity and flexibility, and AA(Acrylic acid) with higher moisturizing to used contact lens materials. AIBN (Azobis2-methylpropionitrile) as initiator and EGDMA(Ethylene Glycol Dimethacrylat) as crosslinking agent were used and the lens with higher oxygen transmissibility and better moisturizing were manufactured complying with basic contact lens properties, which have several combination trial of each monomer characteristics. Compounding SN which included SILICONE, HEMA, NVP and EGDMA etc was showed by swelling ratio of 9.38% and water content of 23.7%. SN was showed by swelling ratio of 9.38%, water content of 23.7% and a visible ray transmissibility of 89%. SB which added BMA in the SN was showed by swelling ratio of 12.50%, water content of 18.56% and a visible ray transmissibility of 88%. SAB which added both AA and BMA in the SN was showed by swelling ratio of 8.33%, water content of 12.93% and a visible ray transmissibility of 88%.