Niu Yujuan, Xiang Feng, Wang Yifei, Chen Jie, Wang Hong
State Key Laboratory for Mechanical Behavior of Materials & School of Microelectronics, Xi'an Jiaotong University, Xi'an, 710049, China.
Phys Chem Chem Phys. 2018 Feb 28;20(9):6598-6605. doi: 10.1039/c7cp08312b.
Surface modification on nanoparticle fillers with organic groups is important to improve the performance of ceramic/polymer nanocomposites. Due to the small coverage level of carboxylic acids on the nanoparticle surface, studies on the use of carboxylic acids as a surface modifier for ceramic nanoparticles have been rarely reported. However, there is no study that proves that a small amount of modifier on the surface of nanoparticles cannot adequately improve the dispersion as well as the compatibility of nanoparticles with the matrix. Herein, we used three carboxylic acids to treat the surface of BaTiO (BT) nanoparticles and adjusted the coverage level of the modifiers on the surface of BT nanoparticles through different ways. The nanocomposite films synthesized from the modified BT nanoparticles dispersed in the poly(vinylidene fluoride) (PVDF) polymer matrix were analyzed by dielectric spectroscopy, breakdown strength, leakage currents, and D-E loop measurements. The results show that the molecule dipole moment and polarizability of the modifier greatly influence the permittivity of the nanocomposites as the surface coverage level of the modifiers increases. Due to many influential factors, changes in the breakdown strength of the nanocomposites show diversity for three modifiers as the modifier content increases. For the nanocomposites applied in energy storage, the optimal content of the modifier on the surface of the nanoparticles needs to be determined by combining various properties of the nanocomposites.
用有机基团对纳米颗粒填料进行表面改性对于提高陶瓷/聚合物纳米复合材料的性能至关重要。由于羧酸在纳米颗粒表面的覆盖水平较低，关于使用羧酸作为陶瓷纳米颗粒表面改性剂的研究鲜有报道。然而，尚无研究证明纳米颗粒表面少量的改性剂不能充分改善纳米颗粒在基体中的分散性以及与基体的相容性。在此，我们使用三种羧酸处理钛酸钡（BT）纳米颗粒的表面，并通过不同方式调节BT纳米颗粒表面改性剂的覆盖水平。通过介电谱、击穿强度、漏电流和D-E回线测量对由分散在聚偏氟乙烯（PVDF）聚合物基体中的改性BT纳米颗粒合成的纳米复合薄膜进行了分析。结果表明，随着改性剂表面覆盖水平的增加，改性剂的分子偶极矩和极化率对纳米复合材料的介电常数有很大影响。由于存在许多影响因素，随着改性剂含量的增加，三种改性剂的纳米复合材料的击穿强度变化呈现出多样性。对于应用于能量存储的纳米复合材料，需要结合纳米复合材料的各种性能来确定纳米颗粒表面改性剂的最佳含量。
