Parametric study on pyroelectric performances of functionally graded graphene nanoplatelet reinforced polyvinylidene fluoride composites

Abstract Polyvinylidene fluoride (PVDF) with pyroelectric properties has demonstrated great potential in sensors, actuators and structural health monitoring. However, the low content of β phase and the secondary pyroelectricity induced by thermal expansion limit its pyroelectric performances for a broader range of applications. In this work, graphene nanoplatelets (GNP) that have excellent physical properties are added to PVDF to improve the matrix's pyroelectric properties. To fully take advantage of the reinforcements, PVDF composite films with functionally graded (FG) distribution of GNP fillers are prepared. The pyroelectric properties of the FG films that are subjected to different scenarios are experimentally tested and analyzed. Combining experiments and finite element simulation, the secondary pyroelectricity of the multi‐layered FG films is particularly investigated for the first time. Compared to uniform dispersion, FG distribution of the GNP has an obvious effect on the pyroelectric performances of the PVDF composites. The increase in the number of layers and the thickness of the outer layers is beneficial for the improvement of the pyroelectric performances. The FG films with higher GNP concentration in the outer layer exhibit more favorable pyroelectricity. The parametric study is envisaged to provide guidelines for the design and optimization of the FG‐GNP/PVDF composites with improved pyroelectric performances. Highlights FG‐GNP is favorable for pyroelectricity and stability of PVDF composite films. GNP/PVDF composite films with more layers demonstrate superior pyroelectricity. Attributes of layers have significant effects on pyroelectric responses. Effects of factors associated with secondary pyroelectricity are quantitatively identified.