Polarization response characteristics of PDMS rectangular laminas with different inner layers under impact load

Abstract

Polydimethylsiloxane (PDMS) dielectric materials, which have a wide application prospect in the field of electromechanical conversion materials, can withstand large deformation. Therefore, it is of great significance to explore the polarization response characteristics of PDMS under impact load. Rectangular PDMS specimens with monolayer structure, inner bonded/unbonded frustum of a pyramid and cone structure were prepared to investigate the structural correlation and internal charge motion of PDMS. The mechanical and polarization characteristics of materials were obtained by using Split Hopkinson Pressure Bar (SHPB) system and digital oscilloscope. The electromechanical coupling numerical simulation of different structural PDMS and the polarization law of PDMS with different structures under impact load were carried out with COMSOL Multiphysics finite element software. The results show that: (i) When impact rod acts on convex surface, the maximum stress induced by PDMS is 2–3 times of that on concave surface; the maximum stress of inner bonded PDMS with frustum of a cone structure is 75% of that with unbonded structure; (ii) The calculated flexoelectric coefficients are as follows: μzzzz = −8.46 × 10−10C/m，μxxzz = 3.32 × 10−10C/m，μxzxz = −3.5 × 10−10C/m; (iii) The polarization voltage of inner bonded PDMS is larger when impact rod acts on concave surface, and the magnitude of voltage induced by inner unbonded PDMS is about 1/10 of that with bonded structure; (iv) The interfacial charge order of inner bonded PDMS is 10 times that of monolayer PDMS, and the polarization voltage induced by coupled electric field is significantly increased.