Large electrostrictive strain at gigahertz frequencies in a polymer nanoactuator: Computational device design

Using molecular dynamics with a first-principles-based force field sdenoted MSXXd, we show that large electrostrictive strains s,5%d at extremely high frequencies sover ,109 Hzd can be achieved in a polysvinylidene-fluorided nanoactuator if the packing density of the polymer chains is chosen appropriately. We control the packing density by assembling the polymer chains on a silicon k111l surface with one-half coverage. Under these conditions, the equilibrium, zero electric field conformation of the polymer contains a combination of gauche and trans bonds. This structure can be transformed to an all-T conformation by applying an external electric field. Such molecular transformation is accompanied by a large deformation in the direction of the polymer chains. The device shows typical electrostrictive behavior with strain proportional to the square of the polarization. © 2005 American Institute of Physics. fDOI: 10.1063/1.1862343g