Contact angle measured on glass

Contact Angles Measured on Glass Plates Covered with Pure PS Layers... 

The formation of monolayers of cerotic, be-henic, and stearic acids adsorbed from cis-decahydronaphthalene and w-hexadecane solutions onto glass was studied by electron microscopy. Platinum preshadowed carbon replicas of the monolayered glass surfaces were examined in a JEM 6-A electron microscope. The acids adsorb initially in discrete patches the average patch diameter depends on the length of the acid molecule, becoming smaller for shorter acids. The area covered by the unimolecular film increases as the adsorption time or concentration of adsorbate solution increases. Contact angle measurements on partially monolayered surfaces show the contact angle to be dependent upon the fraction of substrate covered. Direct evidence of metastable incorporation of hexadecane in acid mono-layers was obtained. 

Wang and Shu [2] obtained transparent superhydrophobic antireflec-tive layers for solar cells. The layers were constructed on a glass substrate using layer-by-layer deposition of a polyelectrolyte. The superhydrophobic sol-gel system was prepared by hydrolyzing tetraethoxysilane and then reacting it with hexamethyldisilazane. The water contact angle measured on the layers obtained by the spin coating method was up to 163° on most superhydrophobic surfaces. Moreover, the transmittance of this layer was about 96%. 

The adsorption of alkyl and aryl isocyanides on Au film [26, 32, 33], powder [36, 37] and nanoparticles [39, 41, 42] has been studied using several different techniques IR methods (RAIR, ATR-IR, DRIFT), Raman methods (SERS), X-ray methods (NEXAFS), ellipsometry (OE, SWE) and contact angle measurements (ACA). The gold surface is not oxidized under normal conditions consequently, the experiments were performed in air at room temperature. The gold film was obtained by physical vapor deposition of 100-200 nm of gold on different substrates glass [28, 33], mica [33], silicon [25, 27, 31, 32], ZnSe crystal [26]. A... 

Thin films of polyethylene, poly(ethylene-co-5-norbomen-2-yl acetate), and poly-(cthylene-co-5-norbomen-2-ol) were prepared on glass slides and contact angle measurements of water droplets determined. Testing results are provided in Table 2. 

DePalma and Tillman investigated self-assembled monolayer films from three silanes, tridecafluorooctyltrichlorosilane, undecyltrichlorosilane, and octadecyl-trichlorosilane, on silicon, a popular model substrate for such studies with great relevance to potential semiconductor coating applications. They characterized the films by ellipsometry and contact angle measurements (data for trideca-fluorooctyltrichlorosilane are included in Table 1), but more usefully from an applicational viewpoint, they carried out friction and wear measurements with a pin-on-disk device where the silicon wafer substrate, coated with monolayer, is moved under a spherical glass slider. Optical microscopy was used to assess wear. Table 2 summarizes DePalma and Tillman s data and their comparison with the classical self-assembled monolayer friction studies of Levine and Zisman [18]. 

Values are mean values with the standard deviation shown in parentheses n=7 in each case, a ESCA measurements on silicon substrates, b Sessile drop measurements on glass slides, c Ellipsometry measurements on silicon substrates, d First receding contact angle. 

Procedure. With the exception of poly (ethylene terephthalate), 20/ films of each polymer were prepared by the evaporation or approximately 4% solutions in quartz or glass dishes of 50 cm.2 area for extraction experiments. For contact angle measurements, films were evaporated on acid-cleaned microscope slides by a dipping technique. Tetrahydrofuran was used with poly (vinyl chloride), methylene chloride with the other polymers. 

Prins and Clint et al. developed a method of contact angle measurement for macroscopic flat foam films formed in a glass frame in contact with a bulk liquid. They measured the jump in the force exerted on the film at the moment when the contact angle is formed. A similar experimental setup was used by Yamanaka for measurement of the velocity of motion of the three-phase contact line. 

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