Preparation And Electro-deformation And Electric Field Induced Modulus Of Dielectric Electrorheological Elastomers

Soft robots have good morphological adaptability and have become a frontier field involving materials,machinery,mechanics and other interdisciplinary fields.Soft deformation materials are the foundation of soft robot development.However,due to the inherent low modulus of soft materials,soft robot is difficult to maintain stability and poor load capacity.The existing solution is to use pneumatic actuator to give the soft robot a variable stiffness function,but there are problems such as complex system and slow response.If the elastic modulus of the soft material can be directly controlled by the electric field,and the integrated intelligent material of deformation and variable stiffness driven by electricity can be developed,the bottleneck problem restricting the development of the soft robot can be solved.Dielectric elastomers（DE）are typical electro-deformable materials,which are widely used in the field of soft robots.While another electro-intelligent material-electrorheological elastomers（ERE）is used in the development of variable stiffness vibration damping devices due to its unique characteristics of electrorheological modulus.In this paper,electrorheological elastomers and dielectric elastomers are combined to construct a dielectric electrorheological elastomer（DERE）with both functions of electro-deformation and electro-variable modulus.It lays a material foundation for the development of new type soft robot with controllable stiffness.Firstly,the electrorheological elastomer was prepared with urea modified Ti O₂ particles as the filling phase,and its electro-viscoelastic and electro-deformation effects were studied.The electro-viscoelasticity test results showed that under the applied electric field of 0～3k V/mm,the storage modulus of the electrorheological elastomer increased with the increase of the electric field strength,and the relative ER effect reached 12%under the electric field strength of 3k V/mm.The result of electro-deformation test showed that the ERE has significant electro-deformation ability.The shape variable of the ERE is 2.8 times higher than that of silicone rubber at the electric field strength of 3k V/mm.The cantilever beam structure based on electrorheological elastomer was constructed,and the change of its stiffness was tested under different applied electric fields.The result showed that the stiffness of the cantilever beam structure of electrorheological elastomer increased with the increase of voltage.Then,dielectric electrorheological elastomer was prepared by laminating ERE with commercial dielectric elastomer VHB4910 and coated with flexible electrode.The electro-deformation behavior,electro-viscoelasticity,recycle stability and creep recovery of DERE and VHB4910 were tested.The experimental results showed that the electro-deformation effect of DERE is 20 times higher than that of VHB4910.And DERE had a significant electrorheological effect:under the electric field of 3k V/mm,the shear storage modulus of DERE was increased by 11%compared with that of zero field.The creep recovery test results showed that the creep strain generated by DERE was small under the same stress,and the residual strain of DERE was small after the stress is removed.The tensile test results after repeated constant extension cycles showed that the mechanical property of DERE after multiple loading was more stable than that of single-layer VHB4910.The creep recovery test results showed that the creep stress of DERE is smaller under the same stress,and the residual stress of DERE is small after the stress is removed.Finally,a soft driver based on DERE was designed and manufactured.The test results show that the driver has remarkable electronic control deformation ability.