High-dielectric-constant elastomer with low dielectric loss improves performance of smart wearables

High-dielectric-constant elastomers possess outstanding softness and stretchability. They allow a fast response and have a high reliability, and thus have been widely applied to wearable electronics.

Prof. Hu Benlin’s team at the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences, has developed an intrinsic ferroelectric elastomer with a high dielectric constant and a low dielectric loss, which can effectively improve the performance and stability of smart wearables.

The study is published in Advanced Materials.

By introducing soft long-chain crosslinking structures into ferroelectric polymer materials with a “slight crosslinking” method, Hu’s team had earlier achieved an intrinsic elastomer with high dielectric constants up to 35.4 at 1 kHz (54.2 at 100 Hz) that balances ferroelectricity and elasticity.

However, the dielectric relaxation and high mobility of the introduced soft long chains under alternating electric fields can trigger serious energy dissipation, leading to substantial dielectric loss.

In their new study, the NIMTE researchers integrated a rigid short-chain crosslinker with the relaxor ferroelectric P(VDF-TrFE-CFE). The obtained intrinsic ferroelectric elastomer showed a low dielectric loss of ~0.09 while maintaining a high dielectric constant of ~35 at 1 kHz and 25°C.

Compared with the soft long-chain crosslinking method, the rigid short-chain crosslinking approach reduced dielectric loss by more than 70%.

In addition to great ferroelectricity, piezoelectricity, and thermal stability, the obtained intrinsic ferroelectric elastomer achieved a high elastic recovery ratio exceeding 70% under 60% strain. The fabricated elastic devices based on the obtained intrinsic ferroelectric elastomer showed stable ferroelectric responses and relaxor characteristics even under 80% strain.

The study provides an effective approach to reducing the dielectric loss of high-dielectric-constant intrinsic elastomers, broadening their applications in wearable electronics, actuation, sensing, information processing, and energy storage.