Effect of Ultrafine Cement Mineral Phase C4AF on the Properties of PVDF Composite Films

Abstract

The development of intelligent buildings requires energy harvesting technology, especially smart piezoelectric materials. This paper mainly explores the possibility of applying polyvinylidene fluoride (PVDF) as a piezoelectric energy storage material in building structures. In order to make PVDF piezoelectric energy storage materials suitable for the cement-based materials, the cement mineral phase tetracalcium aluminate (C₄AF) as filler and PVDF as matrix are used to prepare ultrafine C₄AF-PVDF composite films. The mechanical properties, crystal structure, thermal behavior, electrochemical behavior, and morphology of C₄AF-PVDF composite films are characterized. The results show that a small amount of C₄AF can be uniformly dispersed in the PVDF matrix and fill the pores, which not only maintains the good toughness of the PVDF film but also promotes the nucleation and crystallization of the film. Meanwhile, the conceptual model developed in this paper shows the mechanism of C₄AF on PVDF film in macro and microstructures, explains, and analyzes the influence of C₄AF on the PVDF film matrix from the level of nucleation and crystallization. This paper can provide reference value for the application of cement-based mineral phase materials combined with PVDF in the field of intelligent buildings for piezoelectric energy harvesting.