Solid surface properties

Petroleum reservoirs can exhibit the full range of wettabilities from water-wet to oil-wet (53). Adsorption of crude oil heavy ends modifies solid surface properties and is thought to change reservoir wettability toward more oil-wet. Surfactant adsorption on hydrophobic surfaces takes place by hydrophobic interactions between surfactant hydrocarbon chains and the solid surface (35, 54—58). At low surfactant concentrations, surfactant molecules are oriented parallel to the surface. As the surfactant concentration increases, hydrophobic interactions between surfactant hydrophobes become significant. The surfactant molecules become oriented vertically to the surface with the polar groups toward the aqueous phase. 

In considering solid surfaces, properties such as superficial area, porosity (number and mean diameter of pores), and the existence of acidic and/or basic (from both types Lewis and Bronsted) sites on the surfaces are of prominent importance to understand and predict the chemical behavior of such solids. 

To evaluate reaction rate of gas-solid systems, one must know the solid surface properties. Moreover, the rate constant is the most important parameter for a correct decision about what type of system will be adopted on the problem. 

Solid surface properties based on contact-angle data for selected homopolymers are shown in Tables 59.3 and 59.4. The column of Table 59.3 is the Zisman critical surface tension of wetting [4] obtained from the quasistatic, advancing contact angles 0 of a series of liquids of surface tension 7lv by empirical equation ... 

Surface properties In the interaction of polymers with other materials (liquid or solid), surface properties are critical, (a) The interaction of polymer surfaces with liquids in this case, the important phenomena are the wetting and spreading and these affect the adhesion of polymer surfaces applied in the Uqnid state. When a liquid is brought into contact with a polymeric sohd, the extent of wetting is described by the contact angle 0 which a hquid droplet makes with the surface at the three-phase contact hne. When a hquid wets a polymeric sohd to the extent that the contact angle becomes zero, the equilibrium spreading coefficient S is defined as in Eq. 1.16 ... 

The most important solid surface property is its interaction with gases or liquids. The adsorption of a gas on a solid surface has been known to be of very much important in various systems (especially in industry involved with catalysis, etc.) (Birdi, 2009 Bonzel, 2014 Do, 1998). The gas-solid surface phenomena can be analyzed as follows. 

Adsorption experiments conducted with PEO and alumina particles showed no adsorption of the former on the particles. Because it is known that SDS adsorbs on alumina and that PEO interacts with SDS, PEO adsorption tests were repeated with alumina pretreated with SDS. The authors observed that the presence of a surfactant on the alumina surface caused near-complete adsorption of the polymer as a consequence of its interaction with surfactant aggregates. This result showed that it was possible to force the adsorption of a polymer on a solid surface on which it spontaneously does not adsorb. Instead of drastically modifying the solid-surface properties to force the adsorption of PEO, it seems, by far, more convenient to form surfactant aggregates at the solid-liquid interface and then to allow the polymer to adsorb. 

Solid surface properties homogeneous, hydrophobic surface, not promoting any specific biochemical interaction. 

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