Effective contact angle for rough boundary

In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: a b s t r a c t We provide rigorous justification for the classical Wenzel equation for the roughness enhanced effective contact angle. The minimization of the total surface energy is reformulated into a variational problem. As the size of the roughness becomes small, we show convergence of the minimizer. The limiting minimizer and effective contact angle are explicitly calculated to verify the Wenzel equation.