• Composites Research
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• 제32권2호
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• pp.96-101
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• 2019

섬유와 수지 간 계면접착력은 복합재료 성능과 관련되므로 이를 정확하게 평가하는 것은 매우 중요하다. 본 연구에서는, 피로 하중 조건에서의 마이크로드롭렛 실험에 의한 계면접착력 평가를 실시하였다. 도파민이 적용된 에폭시 수지에 대하여 기계적 물성 및 계면접착력을 측정하였다. 기계적 물성을 평가하기 위해 인장 시편을 제작하였고, 계면 접착력 평가를 위하여 유리섬유에 에폭시 마이크로드롭렛을 만든 시편을 사용하였다. 특히 마이크로드롭렛 피로 실험 시 동일한 직경의 마이크로드롭렛을 사용하여 동일한 조건에서 실험하였다. 그 결과 인장 및 마이크로드롭렛 실험을 통해 에폭시 수지에 도파민이 적용될 때 기계 및 계면접착력이 향상됨을 확인하였다. 도파민이 에폭시 수지의 경화정도를 향상시키고 에폭시 수지에 하이드록실 그룹을 부여하여 기계적 물성 및 유리섬유 간 계면 접착력을 증가시켰을 것으로 사려된다.

• Journal of the Korean Physical Society
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• 제73권11호
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• pp.1787-1793
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• 2018

The power conversion efficiency of perovskite solar cells has reached 23.3%. Although significant developments have been made through intensive studies, the stability issue is still challenging. Passivation of perovskite solar cells with a transparent polymer provides better stability; however, there are a few disadvantages of organic polymer such as low thermal stability, weak adhesion and the lack of water retention ability. In this work, we prepared a dual Parylene-F/C layer with 3-methacryloxypropyltrimethoxysilane, A-174, to combine the advantages of organic and inorganic materials. As a result, A-174 treated dual Parylene-F/C layer demonstrated improved passivation effects compared to a single Parylene layer due to the strong binding of Parylene and the water retention ability by $SiO_2$ formed from A-174. This synergetic effects can be expanded to the combination of other organic materials and organosilane compounds.

• 한국재료학회지
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• 제19권8호
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• pp.437-442
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• 2009

This paper describes an improved strategy for controlling the adhesion force using both the antiadhesion and adhesion layers for a successful large-area transfer process. An MPTMS (3-mercaptopropyltrimethoxysilane) monolayer as an adhesion layer for Au/Pd thin films was deposited on Si substrates by vapor self assembly monolayer (VSAM) method. Contact angle, surface energy, film thickness, friction force, and roughness were considered for finding the optimized conditions. The sputtered Au/Pd ($\sim$17 nm) layer on the PDMS stamp without the anti-adhesion layer showed poor transfer results due to the high adhesion between sputtered Au/Pd and PDMS. In order to reduce the adhesion between Au/Pd and PDMS, an anti-adhesion monolayer was coated on the PDMS stamp using FOTS (perfluorooctyltrichlorosilane) after $O_2$ plasma treatment. The transfer process with the anti-adhesion layer gave good transfer results over a large area (20 mm $\times$ 20 mm) without pattern loss or distortion. To investigate the applied pressure effect, the PDMS stamp was sandwiched after 90$^{\circ}$ rotation on the MPTMS-coated patterned Si substrate with 1-${\mu}m$ depth. The sputtered Au/Pd was transferred onto the contact area, making square metal patterns on the top of the patterned Si structures. Applying low pressure helped to remove voids and to make conformal contact; however, high pressure yielded irregular transfer results due to PDMS stamp deformation. One of key parameters to success of this transfer process is the controllability of the adhesion force between the stamp and the target substrate. This technique offers high reliability during the transfer process, which suggests a potential building method for future functional structures.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 추계학술발표대회 논문집
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• pp.75-78
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• 2005

Using a low-energy Ar+ ion-beam with and without reactive gases, polymers such as chemically stable poly(ether ether ketone) (PTFE) and poly(ether ether ketone) (PEEK) films were modified to have special surface features. The adhesion strength between the polymers and the copper was significantly improved because of both changes in the surface topography and chemical interactions due to polymer surface functionalization (oxidation and amination). The surface modification altered the failure mode from adhesive failure for the unmodified polymer/Cu interface to cohesive failure for the surface-modified polymer/Cu layer interface..

• International Journal of Fluid Machinery and Systems
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• 제3권4호
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• pp.386-395
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• 2010

The article is focused in three areas. In the first part there are analyzed the adhesion forces at the liquid and solid surface interface. There are shown the measured values of surface energy for different types of surfaces. The value of surface energy is decisive for determining the extent of the surface wettability by the liquid. The second part points to the possible negative effects of partly wettable surfaces, showing susceptibility to cavitation. The third section describes the practical aspects of surface wettability by the liquid. Under the new boundary conditions bases, expressing the effect of adhesion forces, there are determined the centrifugal pump characteristics.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.254-255
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• 2005

In this work, the effects of plasma treatment on surface properties of semi conductive silicone rubber were investigated in terms of X-ray photoelectron spectroscopy(XPS). The adhesion characteristics of semiconductive-insulating interface layer of silicone rubber were studied by measuring the T-peel strengths. As a result, semiconductive silicone rubber surfaces treated with plasma discharge led to and increase in oxygen-containing functional groups, resulting in improving the degree of adhesion of the semiconductive-insulating interface layer of silicone rubber. these results are probably due to the modifications of surface functional groups or polar component of surface free energy of the semi conductive silicone rubber.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.249-250
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• 2010

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2004년도 학술대회지
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• pp.301-305
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• 2004

Effects of ion implantation on the adhesion strength of DLC film as a function of ion doses and implanted energies were investigated. Ti ions were implanted on the Si-wafer substrates followed by DLC coating using ion beam deposition method. Adhesion strength of DLC films were determined by scratch adhesion tester. Morphologies and compositional variations at the different ion energies and doses were observer by Laser Microscope and Auger Electron Spectroscopy, respectively. From results of scratch test, the adhesion strength of films was improved as increasing ion implanted energy, however there was no significant evidence with ion dose.

• Composites Research
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• 제34권2호
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• pp.82-87
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• 2021

The mechanical properties of carbon fiber-reinforced epoxy composites (CFRPs) are greatly dependent on the interfacial adhesion between the carbon fibers and the epoxy matrix. Introducing nanomaterial reinforcements into the interface is an effective approach to enhance the interfacial adhesion of CFRPs. The main purpose of this work was to introduce graphitic nanofiber (GNFs) between an epoxy matrix and carbon fibers to enhance interfacial properties. The composites were reinforced with various concentrations of GNFs. For all of the fabricated composites, the optimum GNF content was found to be 0.6 wt%, which enhanced the interlaminar shear strength (ILSS) and fracture toughness (KIC) by 101.9% and 33.2%, respectively, compared with those of neat composites. In particular, we observed a direct linear relationship between ILSS and KIC through surface free energy. The related reinforcing mechanisms were also analyzed and the enhancements in mechanical properties are mainly attributed to the interfacial interlocking effect. Such an effort could accelerate the conversion of composites into high performance materials and provide fundamental understanding toward realizing the theoretical limits of interfacial adhesion and mechanical properties.

• 한국재료학회지
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• 제22권2호
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• pp.66-70
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• 2012

Ti-Ni alloys are widely used in numerous biomedical applications (e.g., orthodontics, cardiovascular science, orthopaedics) due to their distinctive thermomechanical and mechanical properties, such as the shape memory effect, superelasticity and low elastic modulus. In order to increase the biocompatibility of Ti-Ni alloys, many surface modification techniques, such as the sol-gel technique, plasma immersion ion implantation (PIII), laser surface melting, plasma spraying, and chemical vapor deposition, have been employed. In this study, a Ti-49.5Ni (at%) alloy was electrochemically etched in 1M $H_2SO_4$+ X (1.5, 2.0, 2.5) wt% HF electrolytes to modify the surface morphology. The morphology, element distribution, crystal structure, roughness and energy of the surface were investigated by scanning electron microscopy (SEM), energy-dispersive Xray spectrometry (EDS), X-ray diffractometry (XRD), atomic force microscopy (AFM) and contact angle analysis. Micro-sized pores were formed on the Ti-49.5Ni (at%) alloy surface by electrochemical etching with 1M $H_2SO_4$+ X (1.5, 2.0, 2.5) wt% HF. The volume fractions of the pores were increased by increasing the concentration of the HF electrolytes. Depending on the HF concentration, different pore sizes, heights, surface roughness levels, and surface energy levels were obtained. To investigate the osteoblast adhesion of the electrochemically etched Ti-49.5Ni (at%) alloy, a MTT test was performed. The degree of osteoblast adhesion was increased at a high concentration of HF-treated surface structures.