The prediction of wettability of curved surfaces on the basis of the isotherms of the disjoining pressure

The generalization of Derjaguin-Frumkin approach for the description of wettability of curved interfaces is given. The equations for the calculations of the contact angle on concave and convex cylindrical and spherical surfaces based on the isotherms of the disjoining pressure are derived. Analysis performed has shown that for the radius of curvature comparable to the range of surface forces action increasing the surface curvature for convex surfaces results in the contact angle increasing, whereas for concave surfaces the wetting improves. It is shown that curving the substrate surface may cause philic/phobic or phobic/philic wettability transition. (C) 2010 Elsevier B.V. All rights reserved.