Tuning ferroelectricity of polymer blends for flexible electrical energy storage applications

Ferroelectric polymers are the mainstay of advanced flexible electronic devices. How to tailor the ferroelectric polymer films for various applications via simple processing approaches is challenging. Here we demonstrate the tuning of ferroelectric responses can be achieved in polymer blends of poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) and polymethyl methacrylate (PMMA) prepared via a simple two-step process. The proposed two-step process endows the polymer blends with a random distribution of P(VDF-TrFE) crystalline phase, hence decoupling the coherent ferroelectric domain interactions between continuous ordered crystalline phases that ubiquitously existed in common P(VDF-TrFE) film. The incorporation of the miscible non-crystalline PMMA chains with low-polarity results in reversal dipoles and a transition from ferroelectric to antiferroelectric-like behavior, overcoming the trade-off between the polarization and depolarization fields. In particular, resultant excellent mechanical and electrical properties of the polymer blend films give rise to remarkably improved breakdown strength and energy storage performance, surpassing P(VDF-TrFE) and commercial biaxial-oriented polypropylene films. This work provides a simple and effective strategy to tailor the ferroelectric response of polymeric materials with great potential for flexible electrical energy storage applications.