Measurement of the short-range attractive force between Ge plates using   a torsion balance
  We have measured the short-range attractive force between crystalline Ge plates, and found contributions from both the Casimir force and an electrical force possibly generated by surface patch potentials. Using a model of surface patch effects that generates an additional force due to a distance dependence of the apparent contact potential, the electrical force was parameterized using data at distances where the Casimir force is relatively small. Extrapolating this model, to provide a correction to the measured force at distances less than 5 $\mu$m, shows a residual force that is in agreement, within experimental uncertainty, with five models that have been used to calculate the Casimir force. 
W. J. Kim, A. O. Sushkov, D. A. R. Dalvit, and S. K. Lamoreaux