AFM을 이용한 MEMS/NEMS 공정용 재료의 트라이볼로지 특성에 관한 연구

허정철(Jung-Chul Heo),김광섭(Kwang-Seop Kim),김경웅(Kyung-Woong Kim) 한국트라이볼로지학회 2008 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.24 No.2

Friction and adhesion tests were conducted to investigate tribological characteristics of materials for MEMS/NEMS using atomic force microscope (AFM). AFM Si tips were chemically modified with a self-assembled monolayer (SAM) derived from trichlorosilane like octadecyltrichlorosilane (OTS) and (1H,1H,2H,2H-perfluorooctyl) trichlorosilane (FOTS), and various materials, such as Si, Al, Au, Cu, Ti and PMMA films, were prepared for the tests. SAMs were coated on Si wafer by dipping method prior to AFM tip to determine a proper dipping time. The proper dipping time was determined from the measurements of contact angle, surface energy and thickness of the SAMs. AFM tips were then coated with SAMs by using the same coating condition. Friction and adhesion forces between the AFM Si tip modified with SAM and MEMS/NEMS materials were measured. These forces were compared to those when AFM tip was uncoated. According to the results, after coating OTS and FOTS, the friction and adhesion forces on all materials used in the tests decreased; however, the effect of SAM on the reduction of friction and adhesion forces could be changed according to counterpart materials. OTS was the most effective to reduce the friction and adhesion forces when counterpart material was Cu film. In case of FOTS, friction and adhesion forces decreased the most effectively on. Au films.

PMMA 필름의 베이킹 조건에 따른 나노트라이볼로지 특성에 관한 연구

허정철(Jung-Chul Heo),김광섭(Kwang-Seop Kim),김경웅(Kyung-Woong Kim) 한국트라이볼로지학회 2008 한국트라이볼로지학회 학술대회 Vol.2008 No.6

The effect of baking conditions on nanotribological characteristics of thermoplastic polymer film was experimentally investigated. Friction and adhesion forces between Si tip and poly(methyl methacrylate)(PMMA) film were measured using atomic force microscope (AFM). For the tests, PMMA films were prepared on Si wafer by spin coating and baked on a hot plate with different baking conditions; 2 minutes at 80℃, 2 minutes at 140℃, 60 minutes at 140℃, and over 24 hours at room temperature. The results showed that friction and adhesion forces were affected by the baking temperature and baking time. In case of the PMMA film baked for 60 minutes at 140℃, the friction force was the smallest, while the adhesion force was the largest compared to those forces on PMMA films baked with other baking conditions.

연결된 사물인터넷 환경에서의 CMF 디자인 모델 제안

허정철(Jeong-Cheol Heo),정의철(Eui-Chul Jung) 한국HCI학회 2020 한국HCI학회 학술대회 Vol.2020 No.2

제품들이 인터넷을 통해 연결되어 지능적 관계를 형성하는 사물인터넷 환경에서 연결성은 중요한 키워드이다. 독립된 제품과 달리 사물인터넷 환경에서의 제품은 개별적인 기능 외에도 주고받는 데이터를 통해 사용자의 니즈를 충족시킨다. CMF 디자인은 제품의 색상, 재료, 마감(Color, Material, Finish)을 통해서 제품에 기능적, 감성적 특징을 지원하는 디자인 과정이다. 제품들이 인터넷을 통해 연결되어 있는 사물인터넷 환경에서, CMF 디자인 역시 연결성을 고려할 필요가 있다. 본 연구는 연결된 사물 환경에서 사용자의 상황에 따라 다양한 이미지를 생성할 수 있는 CMF 디자인 연구 모델 제안을 목적으로 한다. 연구방법으로 첫째, 사물인터넷의 개념 및 사례, 사물인터넷 환경을 분석하여 연결성을 통한 사물인터넷과 환경의 특성을 이해한다. 둘째, CMF 디자인의 방법론 조사를 통해 현재 독립된 제품의 CMF 디자인 연구 현황을 탐색한다. 셋째, 사례 분석을 통해 연결성에 의해 변화하는 실험적 CMF 가 적용된 디자인을 분석하여 새로운 가능성을 이해하고, CMF 디자인을 설명할 수 있는 모델을 구축한다. 결과적으로, 이 모델을 바탕으로 스마트홈과 자율주행자 실내 환경에서, 연결된 사물의 CMF 디자인의 역할을 설명할 수 있는 시나리오를 제시하여, 모델의 적용 가능성을 논의한다. 이 연구를 통하여, 연결성을 고려한 사물인터넷 CMF 디자인의 컨셉을 제시하고 평가할 수 있는 연구 기반을 수립할 수 있을 것으로 기대한다.

UV-나노임프린트용 UV 경화성 레진의 응착 특성에 관한 연구

허정철(Jung-chul Heo),김광섭(Kwang-Seop Kim),김경웅(Kyung-Woong Kim) 한국트라이볼로지학회 2009 한국트라이볼로지학회 학술대회 Vol.2009 No.6

Adhesion tests were conducted to investigate the adhesion characteristics of UV curable resins for UV-nanoimprint lithography(UV-NIL) application. The UV curable resins used in the tests were AMO-NIL and MINS-UVP 50, and the counterpart was a fused silica lens. Adhesion tests were carried out by a specially designed adhesion force measurement system. In the tests, the UV curable resins spin-coated on Si wafer made contact with the fused silica lens. Then, UV was exposed. After the UV exposure, adhesion force between the UV curable resin and the fused silica lens was measured when the resin was separated from the lens. At the same time, the contact area between the UV curable resin and the fused silica lens was observed by a microscope and a CCD camera Adhesion forces for each UV curable resin were measured under various applied load and separation velocities. The res비st show that the adhesion force per unit area for AMO-NIL was larger than that for MINS-UVP 50. For both of UV curable resins, the adhesion forces per unit area did not depend on the applied load. The adhesion force per unit area increased with the increase of separation velocity for AMO-NIL.

AFM을 이용한 MEMS/NEMS 공정용 재료의 트라이볼로지 특성

허정철(Jung-Chul Heo),김광섭(Kwang-Seop Kim),김경웅(Kyung-Woong Kim) 한국트라이볼로지학회 2007 한국트라이볼로지학회 학술대회 Vol.2007 No.6

Friction and adhesion tests were conducted to study tribological characteristics of materials for MEMS/NEMS using an Atomic Force Microscope (AFM). AFM Si tips were chemically modified with self-assembled monolayer (SAM) derived from trichlorosilane like OTS and FOTS, and various materials such as Si, Al, Au, Cu, Ti and PMMA were prepared for the tests. SAMs were coated by dipping method and they were coated on Si wafer prior to AFM tip to determine a proper dipping condition. The proper dipping condition was determined by the results of contact angle, surface energy and thickness of SAM on Si wafer. AFM tips were then modified with SAMs at the same condition. The friction and adhesion forces between AFM Si tip modified with SAM and MEMS/NEMS materials were measured and compared to those forces when AFM tip was uncoated. According to the results, after coating OTS and FOTS on Si tip, the friction and adhesion forces on the most of materials decreased; however, the effect of SAM on the reduction of friction and adhesion could be changed with counterpart materials. Therefore, the adequate application of SAM would be required to effectively reduce friction and adhesion on each material for MEMS/NEMS.

열가소성 폴리머 필름의 트라이볼로지 특성에 대한 온도의 영향

김광섭(Kwang-Seop Kim),허정철(Jung-Chul Heo),김경웅(Kyung-Woong Kim) 한국트라이볼로지학회 2009 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.25 No.4

Friction tests were carried out in order to investigate the effects of temperature on the friction and wear behaviors between a PMMA film and a fused silica lens using a microtribometer. The friction forces on the PMMA film were measured under atmospheric condition as the temperature of the film was increased from 300 K to 443 K. The contact area between the film and the lens was observed. The tribological characteristics of the film were significantly changed as the temperature increased. The changes were discussed with the change of the film state from glassy to viscous flow. In addition, the results showed that the friction behavior can be varied with the thermal history of the PMMA film. Residual solvent in the PMMA film could emerge to the PMMA surface due to an additional heating and the solvent on the film surface decreased the friction force.

열가소성 폴리머 필름의 마이크로 점착 거동에 대한 온도의 영향

김광섭(Kwang-Seop Kim),허정철(Jung-Chul Heo),김경웅(Kyung-Woong Kim) 한국트라이볼로지학회 2009 한국윤활학회지(윤활학회지) Vol.25 No.2

Adhesion tests were carried out in order to investigate the effect of temperature on the adhesion behavior between a PMMA film and a fused silica lens in the micro scale. For the tests, a microtribometer system was specially designed and constructed. The pull-off forces on the PMMA film were measured under atmospheric condition as the temperature of the PMMA film was increased from 300 K to 443 K and decreased to 300 K. The contact area between the PMMA film and the lens was observed during the test. The adhesion behavior was changed with the change of the PMMA surface state as the temperature increased. In glassy state below 363 K, the pull-off force did not change with the increase of temperature. In rubbery state from 383 K to 413 K, the pull-off force increased greatly as the temperature increased. In addition, the area of contact was enlarged. In viscous state above 423 K, the fingering instability was observed in the area of contact when the PMMA film contacted with the lens. It was also found that the adhesion behavior can be varied with the thermal history of the PMMA film. The residual solvent in the PMMA film could emerge to the PMMA surface due to the heating and reduced the pull-off force.

열가소성 폴리머 필름의 마이크로 점착 거동에 대한 온도의 영향

김광섭(Kwang-Seop Kim),허정철(Jung-Chul Heo),김경웅(Kyung-Woong Kim) 한국트라이볼로지학회 2008 한국트라이볼로지학회 학술대회 Vol.2008 No.11

Adhesion tests were carried out in order to investigate the effect of temperature on the adhesion behavior between a PMMA film and a fused silica lens in the micro scale. For the tests, a microtribometer system was specially designed and constructed. The pull-off forces on the PMMA film were measured under atmospheric condition as the temperature of the PMMA film was increased from 300 K to 443 K and decreased to 300 K. The contact area between the PMMA film and the lens was observed. The adhesion behavior was changed with the change of the PMMA surface state as the temperature increased. In glassy state below 363 K, the pull-off force did not changed with the increase of the temperature. In rubbery state from 383 K to 413 K, the pull-off force increased greatly as the temperature increased. In addition, the area of contact was enlarged. In viscous state above 423 K, the fingering instability was observed in the area of contact when the PMMA film contacted with the lens. It was also found that the adhesion behavior can be varied with the thermal history of the PMMA film. The residual solvent in the PMMA film could emerge to the PMMA surface due to the heating and reduced the pull-off force.

열가소성 폴리머 필름의 마이크로 점착 및 마찰 거동에 대한 온도의 영향

김광섭(Kwang-Seop Kim),허정철(Jung-Chul Heo),김경웅(Kyung-Woong Kim) 한국트라이볼로지학회 2008 한국트라이볼로지학회 학술대회 Vol.2008 No.6

Adhesion and friction tests were carried out in order to investigate the adhesion and friction behaviors between a PMMA film and a fused silica lens and the effect of temperature on the behaviors in the micro scale. For the tests, a microtribometer system was used. The pull-off and friction forces on the PMMA film were measured under atmospheric condition as the temperature of the PMMA film was increased from 300 K to 443 K (heating) and decreased to 300 K (cooling). The adhesion and friction behaviors were changed with the change of the PMMA surface state as the temperature increased. In glassy state below 363 K, the PMMA film was partially tom out due to adhesive friction during sliding and the transfer layer of the PMMA film was formed in the interface. In rubbery state from 363 K to 423 K, the pull-off and friction forces increased greatly as the temperature increased. In addition, the deformation of the PMMA surface was observed due to ploughing friction. In viscous state above 423 K. the fingering instability was observed when the PMMA film contacted with the lens. It was also found that the adhesion and friction behaviors can be varied with the thermal history of the PMMA film. The residual solvent in the PMMA film could emerge to the PMMA surface due to the heating and reduced the pull-off and friction forces.

어머니의 양육태도가 청소년의 자아존중감, 성취동기, 사회성에 미치는 영향에 관한 연구

허정철,김원옥 朝鮮大學校 社會科學硏究所 2005 社會科學硏究 Vol.26 No.2