Contact-angle test

Far from a wellbore, the velocity of reservoir fluids is about one linear foot per day. Near a wellbore, the velocity can increase one-hundred fold. A static or quasi-static test such as the sessile drop (contact angle) test may not represent the dynamic behavior of the fluids in the field. The dynamic Wilhelmy device gives results which are comparable in interface velocity to the field displacement rate. The interface in the Wilhelmy test described here moved at a steady rate of 0.127 mm/sec or 36 ft/day. The wetting cycle for a hybrid-wetting crude oil system was not affected by moving at a rate less than 1 ft/day. 

Contact angle tests showed that the hydrophobic properties on those areas corresponding to the channels had changed substantially (more hydrophilic) compared to other parts of the DL (e.g., those close to the landing widths). The same effect was visible on the surface of the MPL, indicating that loss of the PTFE particles was experienced on both surfaces of the DL. Similar observations regarding the hydrophilicity of the areas in which the FF channels are present were presented previously by St-Pierre and Jia [263]. 

TABLE 2. Contact Angle Testing Results Indicating the Increased Hydrophilicity when Ethylene was Copolymerized with Either 5-Norbornen-2-yl Acetate or 5-Norbornen-2-ol, According to Current Application... 

Surface Tension. Testing for surface tension is sometimes referred to as the contact-angle test (see Fig. 13.6). Surface free energy is defined by surface tension which is directly related to surface cleanliness. If an adsorbate (dirt) is present on a surface, the free energy-surface tension is reduced as energy is spent in bonding the adsorbate to the surface. In other words, the surface has become less clean... 

The aim of the present study was a closer investigation of the properties of LDPE surfaces subjected to photosulfonation processes. Until today no zeta potential studies had been carried out on photosulfonated LDPE. In the present investigation such modified LDPE surfaces were characterized by FTIR spectra, contact angle testing and zeta potential measurements were carried out. To improve the stability of modified LDPE surfaces, polyethylene samples were crosslinked by e-beam irradiation and... 

Viscosity and contact angle testing results are provided in Tables 2 and 3, respectively. 

These properties are listed in order of usefulness for comparative review purposes. Liquid surface tension is the most fundamental property, because it pertains only to the material in question (provided the material is adequately pure) and the technique used for measurement. All the other properties listed are dependent also on solvents, contact-angle test liquids, and liquid or solid substrates selected. For solids, approaches such as the Owens-Wendt analysis (7) have supplanted the Zisman method (18) in recent years, but data from the Zisman method for organosilicon polymers are more available compared with data from the Owens-Wendt approach. Some useful data on aqueous surface tensions and Langmuir troughs are also available. Data for other listed properties are of less fundamental use and rather scanty. 

Table 4.4 Water drop contact angle test on plasma-treated metal surfaces [4], Proc SPIE 2009, reprinted with permission...

The polymer-metal interface between the ionic EAP and the embedded elec-trode(s) was significantly improved using plasma treatment. Based on the water drop surface contact angle tests and mechanical testing, oxygen plasma-treated stainless steel and titanium led to much better adhesion between the electrodes and the EAPs. For both stainless steel and titanium, XPS confirmed the presence of a... 

PLLA Nonwoven scaffold TE SEM, mercury porosimeter, AFM, contact angle test, in vitro neural stem cell culture (Yang et al. 2004)... 

Before actual bonding, the subjective water-break test or the quantitative and objective contact-angle test may be carried out. After bonding, the effectiveness of surface preparation may be determined by measuring the bond strength and determining the mode of the failure of the adhesive joint. 

The contact angles of water and formamide on test materials were measured using the sessile drop method with the contact angle test instrument JCC-1 made in China (Changchun Science Instrument Factory) at 20°C in air. The radius of the... 

As noted above, PMTFPS exhibits somewhat surprising surface properties. According to our measurements, its liquid surface tension is higher than that of PDMS, its critical surface tension using n-alkane contact angle test liquids is similar to the PDMS value, while its solid surface tension judged by the Owens and Wendt [10] approach with water and diiodomethane liquids has a value considerably less than that of PDMS. 

In this table, is calculated from the Girifalco-Good-Fowkes-Young equation [20] using -hexadecane as the sole contact angle test liquid ... 

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