Formation wettability studies

Formation Wettability Studies that Incorporate the Dynamic Wilhelmy Plate Technique... 

This reaction as well as Eq. (56) were confirmed by thermodynamic considerations. Ghetta et al. [328] and Ottavi et al. [339] concluded from wettability studies that the addition of Ti deoxidizes the TiB2 grain surface by the formation of a parasitic Ti(0,C,N) phase. Nevertheless, the sintered density of a material with Fe2Ti addition was rather poor (<89% of theoretical density). The addition of NdNis enhanced the density to 96.7% of theoretical density and resulted in a parasitic Nd203 phase. 

Maoz, R., and Sagiv, J. (1984) On the formation and structure of SAMs I. A comparative ATR-wettability study of LB and adsorbed films on flat substrates and glass microbeads, J. Coll Interf. Sci. 100, 465-496. 

Diamond behaves somewhat differently in that n is low in air, about 0.1. It is dependent, however, on which crystal face is involved, and rises severalfold in vacuum (after heating) [1,2,25]. The behavior of sapphire is similar [24]. Diamond surfaces, incidentally, can have an oxide layer. Naturally occurring ones may be hydrophilic or hydrophobic, depending on whether they are found in formations exposed to air and water. The relation between surface wettability and friction seems not to have been studied. 

The effect of surface contamination and the wettability between the tube wall and the fluids were also studied experimentally. It has been shown that a stable annular flow and gas slug formation with a stable thin liquid film formed between the tube wall and gas slugs, which appeared at high velocities under carefully treated, clean... 

The Wilhelmy hanging plate method (13) has been used for many years to measure interfacial and surface tensions, but with the advent of computer data collection and computer control of dynamic test conditions, its utility has been greatly increased. The dynamic version of the Wilhelmy plate device, in which the liquid phases are in motion relative to a solid phase, has been used in several surface chemistry studies not directly related to the oil industry (14- 16). Fleureau and Dupeyrat (17) have used this technique to study the effects of an electric field on the formation of surfactants at oil/water/rock interfaces. The work presented here is concerned with reservoir wettability. 

A number of studies have examined fibril formation in the presence of different solid nonbiological surfaces, as summarized in Table 1. While many of these studies have focused on the formation of fibrils, the wettability and RMS of some surfaces have been characterized. Typical surface contact angles are also presented in Table 1 to aid comparison between these surface-based experiments. 

To relate the wettability changes more firmly to the photooxidation processes and products, a detailed study was carried out with polystyrene. This polymer was selected because the formation of oxidation products in the hydrocarbon surface gave rise to large changes in wettability and because these products would be readily accessible to optical methods of analysis. The ultraviolet absorption spectrum of polystyrene shows a sharp cut-off, and the extinction coefficients for the radiation absorbed are sufficiently high that almost all of the photochemical reaction should be confined to the surface layers. 

Wettability and Surface Morphology. Surface chemical studies on crystallizable polymers have ignored, in general, the nature of the nucleating phase—i.e., vapor, solid, or liquid—and the details of formation of the polymer melt-nucleating phase interface which on solidification by cooling results in a polymer solid-nucleating phase interface (22). 

The model is straightforward to use, providing point-estimates of exposure. Some databases, especially for mixing/loading of wettable powders and wet-table granules, are rather small and lead to surrogate values that are probably very conservative. An excellent feature of the EUROPOEM model is the fact that it has clearly defined the criteria for selection of studies and exposure data. Such studies have been described in a summary format, because some have a proprietary nature. All data are considered relevant for at least some European conditions and techniques. 

As surfactant is added to the second system of Figure 10, however, the tieline that terminates at the CMC for formation of inverted micelles in the oleic phase is reached before the normal CMC is encountered. Once the former tieline is reached, further additions of surfactant merely increase the concentration of inverted micelles. Only with much larger additions of surfactant will normal micelles begin to form. If only aqueous phases were studied, this could lead to the belief that normal micelles and the associated wettability would be encountered in a flow experiment, when, in fact, inverted micelles and different wettabilities would actually occur. 

Further evidence of film formation has been developed by study of the wettability of polished platinum plates after immersion for one week at 3°C in Chesapeake Bay and Atlantic sea waters followed by rinsing with distilled water and drying. The contact angle of a liquid on a surface becomes smaller with increasing tendency of the liquid to spread on the surface. The contact angles of pure water and methylene iodide on these samples are 27° and 28° for Atlantic water, and 45° and 33° for Bay water (Table I). When compared with values of less than 10° for either liquid on clean platinum, or platinum which has been rinsed in organic media and dried, the presence of a film is apparent. 

For many industrial applications of plastics that are dependent on adhesive bonding, cold gas plasma surface treatment has rapidly become the preferred industrial process. Plasma surface treatment, which is conducted in a vacuum environment, affords an opportunity to minimize or eliminate the barriers to adhesion through three distinct effects (1) removal of surface contaminants and weakly bound polymer layers, (2) enhancement of wettability through incorporation of functional or polar groups that facilitate spontaneous spreading of the adhesive or matrix resin, and (3) formation of functional groups on the surface that permit covalent bonding between the substrate and the adhesive or matrix resin. Since plasma treatment is a process of surface modification, the bulk properties of the material are retained. The nature of the process also allows precise control of the process parameters and ensures repeatability of the process in industrial applications. Finally, several studies have demonstrated that these surface modifications can be achieved with minimum impact on the environment. 

Studies on the use of surfactants as additives in asymmetric membrane preparation have been previously conducted for gas separation and pervaporation processes. However, only few articles reporting the impacts of the surfactants on TEC membrane performance are available [80,81]. As surfactant is capable of altering polymerization efficiency of PA layer formation by helping monomer in the water phase move into the organic layer, improved property of composite membrane is thus able to be produced. In certain cases, surfactant is added to improve wettability of the top surface of the supporting layer so that a greater efficiency of polymerization can take place [82]. 

The wettability of solid surfaces is a veiy important properly of surface chemistiy, which is controlled by both the chemical composition and the geometrical microsttuc-ture of surface [21-23], When a liquid droplet contacts a solid surface, it will sptead or remain as droplet with the formation of angle between the liquid and solid phases. Contact angle (CA) measurements are widely used to characterize the wettability of solid surface. Surface with a water CA greater than 150° is usually called superhydrophobic surface. On the other hand, when the CA is lower than 5°, it is called superhy-drophilic surface. Fabrication of these surfaces has attracted considerable interest for both fundamental research and practical studies [23-25]. 

The effects of air or oxygen plasma on polymer films have been reported. In a comparative study with polypropylene (PP) and polyethylene (PE), higher levels of oxygen incorporation were achieved in PP than with PE. In this method, the initial step involves formation of radicals on the top of the layer of the polymer surface. These can react with each other to initiate cross linking or branching or result in surface oxidation. The use of nonthermal plasma treatment to polymer surfaces to enhance wettability and adhesion has been reported. The use of Corona discharge and dielectric discharge has also been reported for polymer modification [78]. 

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