Analysis of crystallization property of LDPE/Fe₃O₄ nano-dielectrics based on AFM measurements

In this paper, the microstructure of LDPE/Fe₃O₄ nano-dielectric and pure LDPE films are respectively measured through AFM, and the influence of Fe₃O₄ nanoparticles (NPs) and magnetic field processing on the crystallization property of the nano-dielectric films are also analyzed. The result shows that the grown direction of crystal plates in the LDPE matrix is ruleless. While as the doping of the Fe₃O₄ NPs, thickness the crystal plates decreases, and they are packed tightly, this decreases the amorphous area, free volume, and increases the crystallinity of the nano-dielectric film, which proves that the Fe₃O₄ NPs work as heterogeneous nucleating agents in the nano-dielectric films. After magnetic field processing at 130 °C, the oriented growth of the crystal plates increases, and all the crystal plates of the nano-dielectrics films and the LDPE matrix are stretched with different level, which result in the decrease of their crystallinity. All the results are all accordant with that of XRD measurement measured before.