Effect of silicone coupling agent on dielectric properties of barium titanate/silicone elastomer composites

• Piezoelectricity was obtained from nanosized BaTiO3/silicone composites.
• Periodic variation of current that synchronous to stress change was detected out.
• Dielectric property was theoretically discussed from disperse–agglomerate models.
• Normal silicone coupling agent was proved to be effective to improving dispersity.
• Dispersity of BaTiO3 particles was fund to be significant to dielectric property.

BaTiO3 is a type of ceramic with a high dielectric constant, while silicone is a type of elastomer with low elastic modules. Composites made by blending these two materials together can obtain both of their advantages, which has many possible applications in the area of actuators or mechanical sensors. In this study, to improve the dispersity of the BaTiO3 particles, a novel silicone coupling agent was used to modify the surface of the particles. TG and FTIR results showed that the coupling agent was successfully coated on the surface. Raw BaTiO3 and BaTiO3 modified by the silicone coupling agent were incorporated into the silicone elastomer to fabricate the BaTiO3/silicone membranes. Particle size distribution measurements and SEM observations showed that the BT particles can obtain a higher compatibility with the silicone, and both the dispersity of the BaTiO3 particles and the dielectric properties of the BaTiO3/silicone membranes were improved after the surface modification, even without a poling process during the fabrication or measurement. The measuring circuit containing the BaTiO3/silicone membrane is expected to have several applications such as mechanical sensors.

Figure optionsDownload as PowerPoint slide