Effect of surface contact angle on the wall impingement of a power-law liquid jet

Surface tracking has been one of the challenges for outdoor organic insulations, in electronic and electrical devices. In this paper, surface tracking behavior of nano-MgO/epoxy composite samples were measured according to the standard IEC 60112. Improved tracking resistance was obtained in nanocomposites with an 18.75% uplift in the comparative tracking index, and a decrease of 58.20% in the surface ablation area at a fixed 425 V. It was observed that the tracking resistance and surface hydrophobicity shared the same tendency—both, the comparative tracking index and surface contact angle increased with an increase of the nanofiller content. Samples with better hydrophobicity exhibited a higher tracking resistance. It could be the case that the conductive pathway of contamination was harder to form, as a result there were fewer discharging processes. With the development of surface tracking, the surface contact angle abruptly decreased, at first, and tended to be constant, which was also accomplished with the failure of samples. In addition, reduced surface resistivity was also found in the nanocomposites, which was beneficial for releasing surface charges and inhibiting distortions in the electric fields.

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DEVELOPMENT OF CARBON-BASED COATING OF EXTREMELY HIGH TOUGHNESS WITH GOOD HARDNESS

International Journal of Nanoscience ◽

10.1142/s0219581x04002395 ◽

2004 ◽

Vol 03 (04n05) ◽

pp. 571-578 ◽

Cited By ~ 7

Author(s):

S. ZHANG ◽

X. L. BUI ◽

Y. FU ◽

H. DU

Keyword(s):

Residual Stress ◽

Contact Angle ◽

Amorphous Carbon ◽

High Hardness ◽

Hydrophobic Surface ◽

Nanocomposite Coating ◽

High Toughness ◽

Surface Contact ◽

Surface Contact Angle ◽

Carbon Based

Metallic Al was doped into amorphous carbon (a-C) to form a matrix of a-C(Al) of very low residual stress and high toughness at the expense of some hardness. Nanocrystallites of TiC (nc-TiC) of a few nanometers in size were embedded in this matrix to bring back the hardness. The nanocomposite coating of nc-TiC/a-C(Al) was deposited via co-sputtering of graphite, Ti , and Al targets. Although the nanocomposite coating exhibited a moderately high hardness (about 20 GPa), it possessed extremely high toughness (about 55% of plasticity during indentation deformation) and low residual stress (less than 0.4 GPa), smooth (Ra=5.5 nm ), and hydrophobic surface (contact angle with water reaches 100°).

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Comparative Study on Wettability of Typical Plant Leaves and Biomimetic Preparation of Superhydrophobic Surface of Aluminum Alloy

MATEC Web of Conferences ◽

10.1051/matecconf/201814204004 ◽

2018 ◽

Vol 142 ◽

pp. 04004 ◽

Cited By ~ 1

Author(s):

Yanhong Sun ◽

Xinxin Gao ◽

Jinnong Li ◽

Ying Chen

Keyword(s):

Contact Angle ◽

Aluminum Alloy ◽

Comparative Study ◽

Superhydrophobic Surface ◽

Theoretical Research ◽

Plant Leaves ◽

Hydrophobic Property ◽

Direction Parallel ◽

Surface Contact ◽

Surface Contact Angle

The water droplets spread observation, contact angle measurement and SEM analysis, data processing and other means, comparative study of different states of the lotus leaf, rice leaf and nasturtium leaf are carried out. The results show that their surface contact angle of three kinds of plant leaves are all over 140°, they have hydrophobic or superhydrophobic properties; dehydration degree of leaves has little effect on the wettability, will not change its hydrophobic property; the same point of wettability is that they have micro nano composite microstructure. The difference is, the wettability of the lotus and nasturtium is isotropic, while the rice is anisotropic, that is, in a direction parallel to the edge of hydrophobic than perpendicular to the blade edge enhancement. Based on the theoretical research, the hydrophobic surface is copied to the surface of aluminum alloy. The superhydrophobic surface of aluminum alloy matrix was successfully prepared by chemical etching combined with surface fluorination. The super hydrophobic aluminum alloy surface has micron-nano scale double roughness structure; its surface contact angle reached 156°.

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Photocatalytic Surface Modification of PI Film for Electroless Copper Plating

Advances in Condensed Matter Physics ◽

10.1155/2018/1619581 ◽

2018 ◽

Vol 2018 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Wenxia Zhao ◽

Zenglin Wang ◽

Liang Qiao ◽

Shiwei Liu ◽

Hongjian Zhao ◽

...

Keyword(s):

Contact Angle ◽

Surface Modification ◽

Adhesion Strength ◽

Photoelectron Spectroscopy ◽

Carboxyl Groups ◽

Electroless Copper Plating ◽

Electroless Copper ◽

Surface Contact ◽

Surface Contact Angle ◽

Surface Modified

This study investigated the surface modification of polyimide (PI) film through TiO2 photocatalytic treatment. The effects of TiO2 content, treatment duration, and UV power on the surface topography, surface contact angle, and adhesion strength of the surface-modified PI films were investigated. The results indicated that, after surface modification under the optimal photocatalytic conditions, the surface contact angle of the PI film decreased from 84.4° to 38.8°, and the adhesion strength between the PI film and the electroless copper film reached 0.78 kN/m. X-ray photoelectron spectroscopy analysis further demonstrated that carboxyl groups formed on the surface of the PI film after photocatalytic treatment. The surface hydrophilicity and adhesion strength of the surface-modified PI film were enhanced due to the numerous carboxyl groups formed on its surface. Therefore, the photocatalytic treatment is an environmentally friendly and effective method for the surface modification of PI films.

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