• Journal of the Korea Computer Graphics Society
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• v.25 no.1
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• pp.1-11
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• 2019

More force must be applied when dragging a wet compared with a dry cloth lying on the table. Increased force is needed because the fluid between the cloth and the surface of the table produces an adhesion force. In this paper, we study the adhesion force between a wet cloth and the surface of an object. To compute the adhesion force, we used the adhesion force model used in textile research based on real-world experiments and also considered the effect of wrinkles, which, to our knowledge, has not been investigated in previous work. Furthermore, we studied the phenomenon in which a wet cloth adheres to the surface of an object and that in which a wet cloth adheres to itself when undergoing self-collision.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.1
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• pp.240-247
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• 2003

The tribological characteristics of FDTS (1H, 1H, 2H, 2H-Perflurodecyltrichlorosilane) SAM (self-assembled monolayer) and OTS (octadecyltrichlorosilane) SAM treated by high temperature annealing have been investigated from the viewpoint of stiction, adhesion and friction in micro/nano scale. From the experimental results, it was found that OTS SAM gets destroyed at 20$0^{\circ}C$ and stiction, adhesion and friction coefficient increased, but FDTS SAM was stable up to 40$0^{\circ}C$. Also, it was found that the friction coefficient of normal OTS SAM below 20$0^{\circ}C$ is lower than that of FDTS SAM in micro/nano scale, but stiction and adhesion is vice versa. This work shows the importance of surface group of self-assembled monolayer in dictating the tribological characteristics and thermal stability.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.266.2-266.2
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• 2013

According to advanced nanotechnology, the nanostructured materials with various kinds and shape are synthesized easily or produced by process. Recently, researches about interaction between the nanostructured materials and biological system have been progressed actively. The surface topography may influence cellular responses, for example cell adhesion, cell morphology. In this work, we synthesized vertically aligned silicon nanowires (SiNWs) on the Au-covered Si(111) wafer by chemical vapor deposition (CVD) method. We accomplished to control of the SiNWs diameter by regulating thickness of Au film such as 1 nm and 10 nm. These substrates did not isolate cells and just provided surface topography for cell culture. Human Embryonic Kidney 293T cells (HEK 293T cells) were cultured on these substrates for 2 days. We studied the nanotopographical effects on cell morphology, adhesion, and growth which are evaluated on each SiNWs substrate comparing bare glass as control.

• Tribology and Lubricants
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• v.31 no.6
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• pp.264-271
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• 2015

Adhesion force of nanomaterials such as nanoparticle, nanowire, and nanorods should be significantly considered for its mechanical applications. However, examination of the adhesion force is limited since it is technically challenging to carry out experiments with such small objects. Therefore, in this work, molecular dynamics simulation (MDS) was conducted to determine the adhesion force between a nanowire and a flat surface, which could not be readily assessed through experiments. The adhesion force of a cylindrical-shaped nanowire was assessed by performing MDS and applying an equation of Van der Waals interaction. Simulation was conducted in two steps: indentation of a spherical tip on the flat surface and indentation of a cylinder on the flat surface, because the purpose of the simulation was comparing the results of the simulation and calculation of the Van der Waals interaction equation. From the simulation, Hamaker constant used for the equation of Van der Waals interaction was determined to be 2.93 °ø 10?18 J. Using this constant, the adhesion force of the nanowire on the flat surface was readily estimated by calculating Van der Waals equation to be approximately 65~89 nN with respect to the diameter of the nanowire. Moreover, the adhesion force of the nanowire was determined to be 52~77 nN from the simulation It was observed that there was a slight discrepancy (approximately 15~25%) between the results of the simulation and the theoretical calculation. Thus, it was confirmed that the calculation of Van der Waals interaction could be utilized to assess the adhesion force of the nanowire.

• Journal of the Korea Institute of Building Construction
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• v.23 no.4
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• pp.429-440
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• 2023

This research investigates the deployment of waterproofing technologies in construction, with a specific focus on augmenting worker safety, work environment, and solve the difficulty of securing skilled workers. Implementing liquid waterproofing cement equipment resulted in a remarkable increase in adhesion performance by around 20%, coupled with a twofold acceleration in operational speed. The application of primer spraying apparatus led to a two-fold improvement in both penetration and adhesion performance, concurrently boosting the work speed by approximately the same factor. With urethane spraying equipment, the workload could be reduced to a third for the same layer thickness, adhesion performance enhanced by approximately 1.4 times, and workability improved by about 1.4 to 1.5 times. These findings suggest that such technological interventions can potentially enhance work efficiency, improve the quality of output, and mitigate safety accidents that are commonplace in manual operations. Furthermore, these advancements present promising solutions to the ongoing challenges of sourcing highly-competent workers in the industry.

• Journal of Surface Science and Engineering
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• v.49 no.5
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• pp.401-407
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• 2016

In this work, effect of zincate treatment of AZ91 Mg alloy on the following electrodeposition of copper was examined in a non-cyanide bath containing pyrophosphate ions in view of surface morphology and adhesion of the electrodeposited copper layer. Without zincate treatment, the electrodeposited copper layer showed very porous structure and poor adhesion. On the other hand, the copper layer electrodeposited on the zincate-treated surface showed dense structure and good adhesion. The dissolution rate of AZ91 Mg alloy after the zincate treatment appeared to decrease about 40 times in the copper pyrophosphate bath, as compared to that of the surface without zincate treatment. The porous morphology and poor adhesion of a copper layer on the AZ91 Mg alloy surface without zincate treatment were attributed to small number of nucleation sites of copper because of rapid dissolution of the magnesium substrate in the pyrophosphate bath. Based on the experimental results, it is concluded that the zincate treatment to form a conducting and protecting layer on the AZ91 Mg alloy surface is essential for successful electrodeposition of a copper layer on AZ91 Mg alloy with good adhesion and dense structure in the copper pyrophosphate bath.

• Journal of Surface Science and Engineering
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• v.32 no.6
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• pp.647-657
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• 1999

Due to the inherently poor adhesion strength of Cu-based leadframe/EMC (Epoxy Molding Compound) interface, popcorn cracking of thin plastic packages frequently occurs during the solder reflow process. In the present work, in order to enhance the adhesion strength of Cu-based leadframe/EMC interface, black-oxide layer was formed on the leadframe surface by chemical oxidation of leadframe, and then oxidized leadframe sheets were molded with EMC and machined to form SDCB (Sandwiched Double-Cantilever Beam) and SBN (Sandwiched Brazil-Nut) specimens. SDCB and SBN specimens were designed to measure the adhesion strength between leadframe and EMC in terms of critical energy-release rate under quasi-Mode I ($G_{IC}$ ) and mixed Mode loading ($G_{C}$ /) conditions, respectively. Results showed that black-oxide treatment of Cu-based leadframe initially introduced pebble-like X$C_2$O crystals with smooth facets on its surface, and after the full growth of $Cu_2$O layer, acicular CuO crystals were formed atop of the $Cu_2$O layer. According to the result of SDCB test, $Cu_2$O crystals on the leadframe surface did not increase ($G_{IC}$), however, acicular CuO crystals on the $Cu_2$O layer enhanced $G_{IC}$ considerably. The main reason for the adhesion improvement seems to be associated with the adhesion of CuO to EMC by mechanical interlocking mechanism. On the other hand, as the Mode II component increased, $G_{C}$ was increased, and when the phase angle was -34$^{\circ}$, crack Kinking into EMC was occured.d.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.141-141
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• 2013

Shape control of metal nanocrystals has broad applications, including catalysis, plasmonics, and sensing. It was found that controlling the atomic arrangement on metal nanocrystal surfaces affects many properties, including the electronic dipole or work function. Tuning the surface structure of exposed facets of metal nanocrystals was enabled by shape control. We investigated the effect of shape on nanomechanical properties, including friction and adhesion forces. Two nanoparticles systems, high-index {321} and low-index {100}, were used as model nanoparticle surfaces. Scanning force microscopy was used to probe nanoscale friction and adhesion. Because of the abundant presence of high-density atomic steps and kinks, high-index faceted nanoparticles have a higher surface energy than low-index faceted cubic nanoparticles. Due to this high surface energy, high-index faceted particles have shown stronger adhesion and higher friction than low-index nanoparticles. We discuss the results in light of the differences in surface energy as well as the effect of capping layers in the measurement.

• Journal of Surface Science and Engineering
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• v.41 no.1
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• pp.33-37
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• 2008

Polycarbonate has a high transmittance to light, low specific gravity, flexibility and cost-effectiveness that extends the application field of the polymer to bio-engineering, optics, electronic parts, etc. Moreover, electro plating of metallic film on PC could endow the parts the electromagnetic interference shielding capability. However, poor adhesion of copper on PC limited the wide usage in the industry. In this work, a composite(PC/ABS) and MmSH(Momentary mold Surface Heating) injection process were used to improve the plating characteristics; plating thickness, gloss and adhesion. Also plasma treatment and chemical treatment were employed for improving adhesion. Plating characteristics on PC/ABS were better than those on PC due to the anchoring effect of butadiene. MmSH injection process could ameliorate the gloss and coating adhesion. Also plating thickness and adhesion of PC and PC/ABS were increased by plasma treatment.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.2 s.17
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• pp.100-108
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• 2004

Nitramine-polymer composites suffer from a problem known as dewetting. Dewetting adversely affects the performance and the sensitivity characteristics of an explosive composition. Voids, which are generated between explosive particles and binder on dewetting, act as initiation sites. For a PBXs as well as propellants, where good adhesion and mechanical properties are of great importance, dewetting therefore must be prevented by strong adhesion between the filler and the binder. The surface energy of materials is measured by Wilhelmy plate and wicking method. The interfacial energy between the filler and the binder is calculated from the disperse phase and the polar phase of surface energy. Time dependent compressive properties of composite explosives have been determined by stress-strain curves obtained at different strain rates and temperatures. The interfacial state of the PBX was observed through SEM. It was found from the result that the interface between the explosive and the binder becomes better adhesion with decreasing interfacial tension and increasing work of adhesion. The result clearly shows that the castable PBX has good adhesion more than the pressable PBX.