Anisotropic Electrorheological Elastomer With High Performance For Smart Table Tennis Racket

Electrorheological elastomer(ERE)is a kind of smart material whose stiffness can respond to an electric field,appearing after electrorheological fluid and avoiding its existing disadvantages,and possesses wide prospects for application in vibration absorber,noise reduction,intelligent robot,artificial skin and other fields.In this paper,to solve the problems of insufficient electrorheological property and single application mode,we introduced anisotropic structure into ERE by curing under the electric field so that electrorheological property was greatly improved,and applied ERE to smart devices.Then,the morphology and properties of ERE were characterized,and the effect of curing under the electric field on the structure and properties of ERE,as well as internal mechanism,was discussed in detail.(1)The isotropic ERE and anisotropic ERE were prepared by a designed mold with or without an electric field,and observed under optical microscope and scanning electron microscope respectively.It is found that curing under the electric field can effectively make the particles in ERE form chain-like or columnar structures along the direction parallel to the electric field.This anisotropic structure reduces the distance between particles parallel to the direction of the electric field,and produces more small interparticle gaps that are necessary for saturated surface polarization and the local electric field,which contributes to the generation of giant electrorheological effect under the applied electric field,and improves the electrorheological performance of anisotropic ERE,making it significantly higher than that of the isotropic ERE.The highest electrorheological effect of anisotropic ERE under 3 k V/mm reaches the shear storage modulus increment of 5.2 MPa and the relative electrorheological effect of17160%.The compression property of isotropic ERE and anisotropic ERE with or without electric field was tested.The results show that the electrorheological effect of both isotropic ERE and anisotropic ERE can effectively improve the compression modulus,and the compression modulus of anisotropic ERE under the electric field is higher than that of isotropic ERE,and increases with the increase of electric field intensity of curing process.In the compression strain range of 30-45%,the compression modulus of the highest anisotropic ERE sample varies from 2.65 MPa in the absence of voltage to 9.09 MPa in the case of 1.5 k V,with a change rate of 243%.Through the test of dielectric property,the influence of curing under the electric field on the dielectric property of ERE was analyzed,and the improvement of electrorheological property induced by anisotropic structure was further explained.The anisotropic structure improves the dielectric properties of ERE,and increases its effective dielectric constant relaxation strength,thus promoting the electrorheological effect.Isotropic ERE and anisotropic ERE have no significant difference in relaxation time,and both of them have the advantage of short response time.(2)The electrorheological properties of anisotropic ERE within 60 days were studied by measuring it every 15 days.It is found that the shear storage modulus without the electric field increased in the first 15 days,and then the electrorheological properties remained basically unchanged,showing good time stability.In addition,the electrorheological properties of the anisotropic ERE were tested under two modes of cyclic shear and cyclic compression.It is found that the mechanical performance had a growth or fluctuation in the initial stage of two modes,and then tends to stay the same.(3)Based on the high electrorheological properties of anisotropic ERE,a smart table tennis racket with anisotropic ERE applied in compression mode was designed and fabricated.By controlling the electric field intensity applied to ERE in the composite rubber of the smart table tennis racket,the stiffness of the racket face was adjusted,and the movement trajectory of the table tennis ball was changed,and the effectiveness of this function is verified by a series of tests.