Wetting, planar substrate adsorption

Adsorption on Planar Substrates. The simplest type of adhesive bond occurs when a liquid is contacted with a planar solid with which it is totally immiscible and into which it cannot diffuse. Bonding is limited to physical and/or chemical adsorption at specific sites on the substrate surface. A sharp and planar interface is formed. This is the usual situation when an organic adhesive adheres to a very smooth inorganic substrate. The time-dependent process during which interfacial bonds form is called wetting. In general, it involves an increase in the... 

Immiscible Planar Substrates. Consider the simplest case in which a liquid adhesive is placed on a molecularly smooth solid substrate with which it is totally immiscible. The time-dependent process whereby the adhesive and substrate come into intimate contact is called wetting. The interface is a plane across which molecular forces of attraction, also denoted intrinsic adhesion, exist between the liquid and solid. These forces range in magnitude from strong covalent or ionic chemical bonds to weaker physical adsorption, e.g., H-bonding, dipole-dipole, and van der Waals interactions. 

Planar but chemically inhomogeneous substrates are encountered in various practical application, in particular those related to open nanofluidics. One tries to understand the wetting and adsorption properties of such systems in terms of the wetting properties of separate, chemically homogeneous regions. A simple chemical step consists of two semi-infinite planes, each composed of a different material, say, (1) for x < 0 and (2) for... 

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