Wettability sessile drop method

For the DMFC, Zhang et al. [127] used the sessile drop method to study the wettabilities of liquid methanol solutions on the surface of the anode DLs and MPLs. They were able to observe that the contact angles of the materials were the smallest with low PTFE content. In addition, the effect of Nafion ionomer content on the MPL (to increase hydrophilicity see Section 4.3.2) was also shown through the contact angle measurements (i.e., smaller contact angles compared to MPLs with PTFE). 

The wettability of diamond with Ni-Mn alloys having Ga, Ge, Sn, Mg, A1 and Si additives was determined by means of the sessile drop method at high pressure (5.5 GPa) and temperature (1400° C) following a special procedure [3,4]. The metal pellet melted and attained its equilibrium form owing to surface forces on the diamond plane surrounded by molten NaCl that gives a quasi-hydrostatic enviroment and suppress oxidation of the metal. 

The most commonly used is the sessile drop method, and most of the available literature data are for smooth, macroscopic, solid surfaces. Some special problems arise when one is interested in the wettability of finely divided solids. The small size of the particles makes measurement difficult, but, more importantly, surface roughness and particle shape can have a significant effect on the contact angle. 

The contact angle was measured on planed lamellas before bonding in order to determine the wettability of the wood surface with water and with the PF adhesive. The sessile drop method was used to measure the contact angle of a drop deposited... 

The advancing contact angle 0a was measured with the sessile drop method [26]. Two flat plates were used a copper plate with 0a = 62° (good wettability) and an acrylic plate coated with paraffin with 0a = 104° (poor wettability). 

Table II presents the results of some wettability measurements on adsorbed monolayers prepared from molten Compound D on pure, polished, clean, chromium surfaces after solvent treatment had been used to remove all surplus solidified acid. A series of successive solvent treatments was applied to each coated specimen (see first four columns of Table II) using liquids which have been shown to be good solvents for Compound in the bulk (9). These liquids were either absolute ethyl alcohol or benzene at or above 20°C., or n-hexane at or above 60°C. In the remaining columns are listed the average values of the slowly advancing contact angles measured by the drop-buildup method on from three to five different drops. Measurements were made on sessile drops of water, thiodiglycol, and methylene iodide. These three diagnostic liquids were chosen because of their high surface tensions (72.8, 54.0,...

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