I need to do a basic talk for a few minutes on Casimir forces and their effects on nanotechnology. I kind of understand the basic concept of Casimir forces intuitively, as less virtual particles can exist in the standing wave state between the plates than can exist outside of the plates and hence the two plates are driven together. This has a classical analogue in the motion of two ships at sea that are arranged like the two plates, as it was known that the ships would approach one another. I also understand that it is possible to create a repulsive Casimir force by controlling the optical properties of the plates and the mediums they are in. Is there any intuitive way to understand these repulsive Casimir forces or any way of easily explaining the mathematical description? If so, this would be greatly appreciated as I would like to mention how such repulsive forces would help to reduce static friction in nanotechnology.