Ultra-capacitor flexible films with tailored dielectric constants using electric field assisted assembly of nanoparticles
Ultra-capacitor flexible films with tailored dielectric constants using electric field assisted assembly of nanoparticles
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DOI：
10.1039/c5nr06253e
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发表时间：
2015-01-01
期刊：
影响因子：
6.7
通讯作者：
Cakmak, Miko
中科院分区：
文献类型：
--
作者：
Batra, Saurabh;Cakmak, Miko
在这项研究中，链和优先排列的钛酸钡纳米粒子（100 nm）通过聚合物基体的厚度方向在电场的存在下示出。在分散良好的溶液中施加AC电场导致由于介电电泳而在电场方向上以其主轴取向的离散行中的纳米颗粒链的形成。这些链的取向的变化通过SEM图像的统计分析进行量化，并被发现是依赖于电场，频率和粘度。当施加DC场时，用微计算机断层扫描观察到由致密颗粒组成的明显层。这些研究表明，直流电压的增加导致颗粒富集层的厚度沿着增加，同时填充密度也增加。由于在“Z”方向上形成颗粒链而增加颗粒之间的相互作用降低了临界逾渗浓度，在该临界逾渗浓度以上发生性质的显著增强。因此，这种制造方法显示出通过增强给定浓度的介电性质或降低给定性质所需的纳米颗粒浓度来降低包括电容器在内的一系列应用的产品成本的前景。
In this study, the chaining and preferential alignment of barium titanate nanoparticles (100 nm) through the thickness direction of a polymer matrix in the presence of an electric field is shown. Application of an AC electric field in a well-dispersed solution leads to the formation of chains of nanoparticles in discrete rows oriented with their primary axis in the E-field direction due to dielectrophoresis. The change in the orientation of these chains was quantified through statistical analysis of SEM images and was found to be dependent on E-field, frequency and viscosity. When a DC field is applied a distinct layer consisting of dense particles was observed with micro-computed tomography. These studies show that the increase in DC voltage leads to increase in the thickness of the particle rich layer along with the packing density also increasing. Increasing the mutual interactions between particles due to the formation of particle chains in the "Z"-direction decreases the critical percolation concentration above which substantial enhancement of properties occurs. This manufacturing method therefore shows promise to lower the cost of the products for a range of applications including capacitors by either enhancing the dielectric properties for a given concentration or reduces the concentration of nanoparticles needed for a given property.