The elasticity and the piezoelectricity of thick composites of silicone rubber matrix and aligned piezoelectric ceramic particles

‘Aligned-type’ piezoelectric rubber is a composite of piezoelectric ceramic, lead zirconate titanate (PZT) particles, which are aligned in a silicone rubber matrix. The aligned-type piezoelectric rubber has both elasticity and piezoelectricity. PZT, a piezoelectric ceramic, does not have elasticity. Also, piezoelectric polymers such as polyvinylidene difluoride (PVDF) have elasticity but can only form a thin film. The conventional aligned-type piezoelectric rubber (CAT) is as thin as about 2 mm, has a high spring constant. Therefore, a thick aligned-type piezoelectric rubber (TAT), having a thickness of 10 mm was fabricated by a new method, the “inversion method”. The TAT was possible to reduce the spring constant to less than 1/5 of that of the CAT while maintaining the piezoelectricity (d33) equivalent to the CAT. Also, the d33 of the TAT is more than twice that of PVDF, and it is Young’s modulus is less than 1/200 that of PVDF.