Improvement of Hydrophobic Property of Stainless-Steel Plates by Forming Lens-Like Protrusions Similar to Oxalis Leaf Surfaces

2019 ◽  
Vol 813 ◽  
pp. 19-24
Author(s):  
Toshiyuki Horiuchi ◽  
Yoshie Imon ◽  
Kazuya Sumimoto ◽  
Akira Yanagida ◽  
Hiroshi Kobayashi

Leaves of an obscure plant “oxalis deppei” are so hydrophobic that showered water droplets are almost completely repelled and hardly remained on their surfaces. For this reason, surface configurations were investigated. On the live leaves, there formed protrusions somewhat similar to those observed on lotus leaves which are well known as super hydrophobic leaves. However, in winter, it was found that even dead leaves were hydrophobic also. Because leaf tissues were shriveled and dried half, heights of protrusions with sizes of 20-50 μm were low, and undulations of surfaces were gentle and smooth, and pitches of undulations were as large as 30-70 μm. It was thought that such gentle lens-like protrusions would be probably formed on versatile stainless-steel plates using lithography and wet chemical etching. For this reason, arrays of protrusions with a size of 20 μm, a pitch of 35 μm, and heights of 6-7 μm were formed, and change of hydrophobic properties were investigated. As a result, the hydrophobic properties were effectively improved by forming even such gentle and smooth protrusions. It was also clarified that contact angles were improved almost in proportion to etched depths.

2013 ◽  
Vol 395-396 ◽  
pp. 718-725 ◽  
Author(s):  
Shen Chun Wu ◽  
Dawn Wang ◽  
Hsih Shing Li ◽  
Sin Jie Lin ◽  
Chao Tsai Hsu ◽  
...  

This study investigated the use of nanoscale bilayers assembly film for hydrophilic surface modification on stainless steel plates and observed its effects on the evaporation of acetone and ethanol on the plates. This study first established the nanoscale bilayers assembly technique, and then performed hydrophilic surface modification on stainless steel plates by changing the surface structure, producing different contact angles. The relationship between the number of bilayers (10, 20, and 30) and the resulting contact angle was empirically determined; results indicated that 20-bilayer modification yielded the best result, reducing the contact angle from 70° (unmodified surface) to 12°. Beyond 20 bilayers, at 30 bilayers, the samples show no significant changes or improvements to contact angle or hydrophilicity. Results from evaporation time tests showed that, compared to the evaporation time of ethanol and acetone on unmodified flat stainless steel surface, this decreased contact angle can improve the evaporation time by 100%, clearly indicating that hydrophilic surface modifications causes significant improvement in evaporation.


Author(s):  
Dongmei Meng ◽  
Joe Rupley ◽  
Chris McMahon

Abstract This paper presents decapsulation solutions for devices bonded with Cu wire. By removing mold compound to a thin layer using a laser ablation tool, Cu wire bonded packages are decapsulated using wet chemical etching by controlling the etch time and temperature. Further, the paper investigates the possibilities of decapsulating Cu wire bonded devices using full wet chemical etches without the facilitation of laser ablation removing much of mold compound. Additional discussion on reliability concerns when evaluating Cu wirebond devices is addressed here. The lack of understanding of the reliability of Cu wire bonded packages creates a challenge to the FA engineer as they must develop techniques to help understanding the reliability issue associated with Cu wire bonding devices. More research and analysis are ongoing to develop appropriate analysis methods and techniques to support the Cu wire bonding device technology in the lab.


Small ◽  
2020 ◽  
Vol 16 (51) ◽  
pp. 2007045
Author(s):  
Mei Sun ◽  
Bocheng Yu ◽  
Mengyu Hong ◽  
Zhiwei Li ◽  
Fengjiao Lyu ◽  
...  

Author(s):  
Albert Grau-Carbonell ◽  
Sina Sadighikia ◽  
Tom A. J. Welling ◽  
Relinde J. A. van Dijk-Moes ◽  
Ramakrishna Kotni ◽  
...  

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