Casimir Forces between Nanoparticles and Substrates
  We study the Casimir force between a nanoparticle and a substrate. We consider the interaction of metal nanoparticles with different substrates within the dipolar approximation. We study the force as a function of the distance for gold and potassium spheres, which are over a substrate of titanium dioxide, sapphire and a perfect conductor. We show that Casimir force is important in systems at the nanometer scale. We study the force as a function of the material properties, radii of the spheres, and the distance between the sphere and the substrate. 
C. E. Roman-Velazquez, Cecilia Noguez, C. Villarreal and R.   Esquivel-Sirvent