Why we need 6000 Volatge for microgripper

In the microgripper model given at comsol website at link

www.comsol.co.in/showroom/down...e/models.mems.microgripper.pdf

It is written to apply a volatge of 6000 Volt.(written on page 2 of the paper)
My question is why we need such a high voltage for this model.
The actulal microgripper available in the market operate at 5 v only.

Please try to repond asap.

Thanks...