On the Influence of Relative Humidity on the Contact Angle of a Water Droplet on a Silicon Wafer

Author(s):  
J. L. Perez-Diaz ◽  
M. A. Alvarez-Valenzuela ◽  
I. Valiente-Blanco ◽  
S. Jimenez-Lopez ◽  
M. Palacios-Cuesta ◽  
...  

Contact angle analysis of liquids on surfaces has been extensively used to evaluating solid surface free energy, surface tension, and surface wetting characteristics. Despite the great interest in the contact angle, reported measurements has shown a high variety, which is often related to different contact angle measurement techniques or substrate preparation and oxidation among others. In addition, it is well know, that surface tension and contact angle are modified with temperature. However, no attention has been paid to the influence of the relative humidity (RH) in surface tension or contact angle measurements. In a previous work, we have demonstrated that (for a constant temperature) surface tension on a suspended droplet decreases linearly with RH in the air. In this paper, contact angle of a water droplet on a silicon wafer surface is studied and its relationship with the relative humidity in the air investigated.

Holzforschung ◽  
2001 ◽  
Vol 55 (1) ◽  
pp. 21-32 ◽  
Author(s):  
M.E.P. Wålinder ◽  
I. Johansson

Summary This work focuses on the influence of extractives during wetting measurements on wood. Fresh and aged veneers of extracted and non-extracted heart- and sapwood of pine were prepared, and the Wilhelmy method was used to study the wettability of these veneers. In this method, the force acting on the veneers was measured during immersion in and withdrawal from a series of probe liquids. The results suggest that some of the probe liquids become severely contaminated by extractives during the measurements on the non-extracted veneers, and that this strongly affects the wood wetting measurements. The contamination is effectively detected as a distinct decrease in the surface tension of the liquids caused by dissolution or presence of wood extractives at the wood-liquid interface. It is important to note that such contamination may also occur during wetting studies on wood using other contact angle measurement techniques. The most obvious contamination occurred in the case of measurements on non-extracted veneers immersed in water and formamide. Generally, no contamination was detected in the case of measurements on extracted wood veneers. The Wilhelmy method may provide an efficient means for recording and control of any contamination of the probe liquids that may arise during wetting studies on wood.


2007 ◽  
Vol 19 (5-6) ◽  
pp. 700-710 ◽  
Author(s):  
Yasuko Yamada ◽  
Tomoyasu Hirai ◽  
Ryohei Kikuchi ◽  
Teruaki Hayakawa ◽  
Masa-Aki Kakimoto

Triethoxysilyl functionalized hyperbranched polsiloxysilanes at the focal (FT-HBPSs) and terminal (TT-HBPSs) positions were synthesized to investigate adsorption behavior onto a silicon wafer surface. The surface of the silicon wafer adsorbed with the HBPSs was characterized by X-ray photoelectron spectroscopy, atomic force microscopy (AFM), static and dynamic water contact angle measurements. The AFM images indicated the formation size of dot-like structures were approximately 200 nm. The presence of vinyl terminal groups of FT-HBPSs permitted conversion of the surface from a non-polar hydrocarbon to a polar hydroxylated or carboxylated structures. After the polarity was changed, the surface properties were also studied using the above surface analysis techniques. The dynamic contact angle measurement indicated that the silicon wafer surface modified by FT-HBPSs was more hydrophilic in water than TT-HBPS. This behavior can be explained by the difference of connecting points between HBPS and the silicon wafer surface.


2013 ◽  
Vol 11 ◽  
pp. 487-494 ◽  
Author(s):  
Chin Fhong Soon ◽  
Wan Ibtisam Wan Omar ◽  
Nafarizal Nayan ◽  
Hatijah Basri ◽  
Martha Bt. Narawi ◽  
...  

2014 ◽  
Vol 979 ◽  
pp. 355-358 ◽  
Author(s):  
Tanattha Rattana ◽  
Nirun Witit-Anun ◽  
Sumetha Suwanboon ◽  
Surasing Chaiyakun

In this work, TiO2thin films were prepared by a sol-gel spin coating method on glass slide, stainless steel 304 and silicon wafer substrates. The thin films were annealed at different temperatures at ambient atmosphere. The effect of substrates and annealing temperatures on microstructure, surface morphology and hydrophilicity of the films were characterized by Raman spectroscopy, atomic force microscopy and water contact angle measurement, respectively. The Raman spectra indicated that the annealed TiO2thin films (at 550 °C) coated on stainless steel and silicon wafer exhibited anatase structure. The contact angle of all samples decreased with increasing the UV-irradiation time and annealing temperature.


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