A modified self-consistent computational model for an electrostrictive graft elastomer

Abstract

An electrostrictive graft elastomer, as recently developed by NASA, is a type of electro-active polymer. In this paper, a 2D computational model with a self-consistent boundary is developed. Firstly, three-dimensional deformations, induced by both bending angle and dihedral torsional angle changes, are projected onto a two-dimensional plane. Using both theoretical and numerical analyses, the projected 2D equilibrium bending angle is shown to have the same value as the 3D equilibrium bending angle. The 2D equivalent bending stiffness is derived using a series model based upon the fact that both bending and dihedral torsion produce a configurational change. Equivalent stiffness is justified by polymer chain end-to-end distance characteristics. Secondly, a self-consistent scheme is developed to eliminate the boundary effect. Eight images of the unit cell are created peripherally, with the original unit cell in the center. Thus the boundary can only affect the rotation of the eight images, not the central unit cell. A computational model is employed to determine the electromechanical properties of the electrostrictive graft elastomer. Relations between electric field induced strain and electric field strength are calculated. The effect of molecular scale factors, such as free volume fraction, graft weight percentage and graft orientation, are also discussed.

Reversible switching transitions of stimuli-responsive shape changing polymers

“…17. 400 Metal electrodes are fabricated on opposite sides of electrostrictive gra elastomer lms. Graed chains forming crystalline domains generate dipole moments and respond to an applied electric eld.…”

“…The strain induced by the applied electrical eld is dependent on the free volume fraction, crystalline gra unit mass percentage, and molecular orientation of the gra elastomer. 365,401 Electroactive liquid crystal elastomers are made of monodomain nematic liquid crystal elastomers incorporated with conducting ingredients. Joule heating induced by an electric eld can change the orientation of ordered liquid crystal groups to produce anisotropic deformations.…”

A Brief Review of Stimulus-active Polymers Responsive to Thermal, Light, Magnetic, Electric, and Water/Solvent Stimuli

“…The local backbone reorientation and crystal unit rotation cause electrostrictive deformation. The strain induced by the applied electrical field is dependent on the free volume fraction, crystalline graft unit mass percentage, and molecular orientation of the graft elastomer (Su et al, 1999;Wang et al, 2003;Sun et al, 2004Sun et al, , 2008. The profound advantage of electrostrictive graft elastomers is its high stiffness compared to other electrostrictive polymers such as silicon rubber and polyurethane (Wang et al, 2004;Sun et al, 2008).…”

Wirelessly driven electro-active paper actuator made with cellulose–polypyrrole–ionic liquid and dipole rectenna

“…Many EAP materials have been developed so far: electronic EAP materials, such as electrostrictive, electrostatic, 1 Author to whom any correspondence should be addressed. piezoelectric and ferroelectric materials [2][3][4][5]; and ionic EAP materials, such as gels, ionic polymer-metal composites, conductive polymers and carbon nanotubes [6][7][8][9]. Due to their characteristics, these materials have advantages and disadvantages as EAP materials, for example, high actuation voltage for electronic EAP materials and a wetness requirement for ionic EAP materials.…”