Vapor Pressure of a Curved Surface

The pressure difference across a curved surface also affects the vapor pressure over such a surface. This pressure over a convex surface happens to be 

Effect of Particle Radius on Pressure Difference and Relative Vapor Pressure 

Material Surface Diameter (H) Pressure Difference, MPa Relative Vapor Pressure, (P/Po) 

V is the molar volume of the material having the convex surface, p is the vapor pressure over the convex surface, and po is the vapor pressure over the planar surface. Therefore, 

Equation 18.106 tells us that the difference in vapor pressure increases with a decrease in particle size. Table 18.1 illustrates this point. Clays are widely used in the manufacture of products out of ceramics and refractories. Qays are characterized by fine particle sizes. Because fine particles have a large surface area per unit volume, the greater surface energy forces bring about good sinterability in clay-mixed green products. 

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Adsorption studies leading to measurements of pore size and pore-size distributions generally make use of the Kelvin equation which relates the equilibrium vapor pressure of a curved surface, such as that of a liquid in a capillary or pore, to the equilibrium pressure of the same liquid on a plane surface. Equation (8.1) is a convenient form of the Kelvin equation ... 

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