Papers by Keyword: Contact Angle (CA)

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Authors: Ja Hyung Han, Ja Eung Koo, Kyo Se Choi, Byung Lyul Park, Ju Hyuk Chung, Sang Rok Hah, Sun Yong Lee, Young Jae Kang, Jin Goo Park
Abstract: The prevention of watermark defect after copper/low-k CMP is a critical barrier for the successful integration of sub-100 nm devices. The water-mark can act as a leakage source and cause electrical shorts. The mechanism of water-mark formation during Cu/low-k CMP is suggested and its prevention methods are proposed in this study. A suitable surfactant treatment can improve the wettability of low-k films and reduce the watermark defects very effectively. The relatively stable low-k film surface is activated during polishing and prone to adsorb surfactant molecules during cleaning, which results in the reduction of water-marks after CMP. Another solution to eliminate water-mark is the application of IPA dryer in post CMP cleaning.
Authors: Yi Kai Chen, Xue Bin Zheng, Baoe Li, You Tao Xie, Chuan Xian Ding, Soo Wohn Lee
Abstract: In this paper, antibacterial silver-containing hydroxyapatite coating was prepared by vacuum plasma spraying method and osteoblasts were seeded onto the surface of the coating to evaluate its cytocompatibility. The results indicated that the cells proliferated well on the samples, and the proliferation rate on the silver-containing hydroxyapatite coating was a little bit higher than that on the silver-free hydroxyapatite coating. The contact angle of water drop on the coating was measured, and it was found that the contact angles of the silver-containing hydroxyapatite coatings were smaller than the hydroxyapatite coating. The improvement of hydrophilicity for the silver-containing hydroxyapatite coating could be beneficial to the cells proliferation on its surface. It can be concluded that the addition of silver in the hydroxyapatite coating endowed the coating with antibacterial property while maintaining its excellent cytocompatibility.
Authors: Yun Fu Chen
Abstract: For finding influence of the condensing surface to dropwise condensation heat transfer, a fractal model for dropwise condensation heat transfer has been established based on the self-similarity characteristics of droplet growth at various magnifications on condensing surfaces with considering influence of contact angle to heat transfer. It has been shown based on the proposed fractal model that the area fraction of drops decreases with contact angle increase under the same sub-cooled temperature; Varying the contact angle changes the drop distribution; higher the contact angle, lower the departing droplet size and large number density of small droplets; dropwise condensation translates easily to the filmwise condensation at the small contact angle ;the heat flux increases with the sub-cooled temperature increases, and the greater of contact angle, the more heat flux increases slowly.
Authors: Feng Guo, Xun Jia Su, Gen Liang Hou, Zhao Hui Liu, Hai Peng Jia
Abstract: Superhydrophobic surfaces have been a hot topic during the last decade owing to their great potential in widely application. In this work, we report on a facile and low-cost two-step method to fabricate superhydrophobic surface on steel substrates. The as-obtained surface shows an interesting hierarchical structure composed of microscale flowerlike cluster and nanoscale particles, which is similar to that of a lotus leaf. After further modification with stearic acid, the resultant surface exhibits remarkable superhydrophobic properties. The water contact angle is as high as 155°. Moreover, the superhydrophobic properties are long-term stable.
Authors: Z. Weltsch, A. Lovas
Abstract: The wetting angles (Θ) of Ag-M based melts (M: Cd, Sn, Sb) on graphite and Al2O3 substrates are compared. Despite of the inert chemical character and the similar surface roughness of substrate materials, the wetting angle is smaller on the Al2O3. The compositional and concentration dependence of Θ exhibits similar trends, than that, observed in the bulk transport properties such as the specific electrical resistance or the thermopower obtained on the same alloys in solid state. No segregation effects can be detected on the solidified metal drops.
Authors: Ling Jia, Bei Qing Huang, Xian Fu Wei, Na Feng
Abstract: Water-based ink in low-energy surface wetting more difficult and hinder its application. In order to solve water ink in low-energy on the surface wettability problem, change the kind of cosolvent, kind and content of surfactants prepared ink. They were tested in low-energy CD the surface contact Angle to examine wettability of ink, test the surface tension, ink affecting wettability factors were analyzed. Results show that: in water-based ink add isopropyl alcohol, flow ping agent 432 and substrate wetting agent 245, can better improve its surface wettability in low-energy, and base material wetting agent 245 content about 1.25% wet effect is good.
Authors: N. Atthi, O. Nimittrakoolchai, Sitthisuntorn Supothina, J. Supadech, W. Jeamsaksiri, A. Pankiew, C. Hruanun, Amporn Poyai
Abstract: Two different viscous coating materials, which are Polydimethylsiloxane (PDMS) mixed with 10%wt of Dicumylperoxide (DCP), and Semifluorinate Silane (SFS), were applied to silicon micro-asperity. The cosine’s Young and viscosity of those coating materials are -0.3584,-0.3496 and 3.176x10-3, 1.339 x10-3 Pas, respectively. The rough surfaces with nine asperity shapes were studied. The results shown that, pillar shape has an effect on water contact angle (WCA): Stripe asperity cannot make the average WCA greater than 150. When consider the pillar asperity, the WCA falls between 152 and 157, which exhibits a superhydrophobic surface property. However, actual WCA of the micro-asperity coated with PDMS+10%wt of DCP is lower than that coated with SFS around 1 to 7. High viscous material makes the asperity size bigger than the design and decreases the WCA: the low viscous material is more suitable for coating on the asperities.
Authors: Jeerachai Supasuthakul, Peter D. Hodgson, Matthias Weiss, Chun Hui Yang
Abstract: Analytical modelling of deep drawing process is of value in preliminary process design to illustrate the influence of major variables including friction and strain hardening on punch loads, cup dimensions and process limits. In this study, analytical models including theoretical solution and a series of finite element models are developed to account for the influences of process parameters including friction coefficient, tooling geometry and material properties on deep drawing of metal cups. The accuracy of both the theoretical and finite element solutions is satisfactory compared with those from experimental work.
Authors: Sunao Murakami, Tsuyoshi Ikehara, Mitsuo Konno, Ryutaro Maeda, Takashi Mihara
Abstract: Additional formation of functional films on the defined micro-areas on the microstructure is often complicated and need advanced control technique. Any simple and faster deposition processes are favorable. In this paper, we propose a simple processing method to form thin films on the defined areas by falling dispersion liquid containing the coating materials on a tilted silicon substrate with trench frames. We attempted to hold the coating solution and to form a thin film within the framed micro-area. We fabricated 500 nm-wide trench frames on silicon substrates, and flew a diluted photoresist (PR) solution, as the coating solution, on the tilted surface with the frames. PR film was successfully formed on the framed area for the substrate modified with hexamethyldisilazane (HMDS). However, the area-selective PR deposition was difficult in case the substrate was not treated with HMDS. It is likely that lower contact angle for the substrate without HMDS treatment is unfavorable for the area-selective PR deposition for the excess adhesive properties of the coating solution to the surface. The effectiveness of the frames as the guide to hold a liquid droplet within the defined area was considered.
Authors: Lan Liu, Zhao Xia He, Xiao Cai Zhang
Abstract: A mathematic model of ball screw was constructed which was based on the elastic contact deformation theory. The helix angle was considered and the formula of axial elastic deformation was deduced in this study. Furthermore, a finite element model of ball screw was established and its elastic deformation results were also acquired. And the effect of contact angle on axial elastic deformation was analyzed by theoretic method and FEA. The study shows that the axial elastic deformation of ball screw changes with the contact angle. The deformation will decrease by the contact angle increasing, and the positional accuracy of the ball screw is improved.
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