Towards complex microarchitectural nanocomposites using non-uniform multi-field processing
Towards complex microarchitectural nanocomposites using non-uniform multi-field processing
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使用非均匀多场处理实现复杂的微结构纳米复合材料
DOI：
10.1117/12.2515259
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
vonLockette, Paris
中科院分区：
文献类型：
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作者：
Al Masud, Md;Erol, Anil;Edson, Connor;Ounaies, Zoubeida;vonLockette, Paris
在这项研究中，我们研究了磁性钡六角铁氧体（BF）片晶在聚二甲基硅氧烷（PDMS）中的分层微结构的形成，使用电场和磁场组装技术。首先，在固化复合材料之前，将外场施加到胶体溶液以形成微观结构。在微结构形成之后，将复合材料热固化以冻结微结构。在这项研究中，我们研究了两种不同的情况-（1）磁场处理的复合材料和（2）多场处理的复合材料，这是在磁场和电场下处理。我们观察到，由于同时施加电场和磁场而形成的宏链与仅由于磁场而形成的宏链相比具有更高的长度。对于这两种情况下，个别BHF被发现是在外部场的方向取向。使用ImageJ和MATLAB对SEM微观结构的分析表明，在这两种情况下，微观结构中存在至少两个不同级别的层次结构，它们被称为压边力堆叠和微链。从实验的定量微观结构分析，BHF被发现是稍微更好地定向（磁易轴方向，相对于外部场）在所有尺度的电场和磁场处理的复合材料相比，只是磁场处理的复合材料。聚合物颗粒混合物的磁电流体动力学模型预测了类似的行为。进行计算模拟，其中允许经受由施加的电场产生的DEP力和响应于施加的磁场的磁偶极子相互作用的颗粒在锁定在最终结构中以表示固化之前形成准平衡结构。模拟的结果证实了与仅磁场相比，在磁场和电场的情况下，与实验类似的更长的大链形成的发现。从模拟的微观结构的分析也证实了多层次的层次结构中存在的复合材料的微观结构的两种情况。在未来，量化层次结构中每个级别的相应指标将有助于更好地理解微观结构，并可作为模型的输入，也可用于验证模型。
In this study, we investigate the hierarchical microarchitecture formation of magnetic barium hexaferrite (BF) platelets in polydimethylsiloxane (PDMS) using electric and magnetic field assembly technique. First, external fields are applied to the colloidal solution to form the microstructure before curing the composites. After microstructure formation, the composites are thermally cured to freeze the microstructure. We investigate two different cases in this study-(1) magnetic field processed composites and (2) multi-field processed composites, which were processed under both magnetic and electric fields. We observe that macro-chains formed due to simultaneous application of electric and magnetic fields had a much higher length compared to the macro-chains formed due to just magnetic field. For both cases individual BHFs are found to be oriented in the direction of the external field. The analysis of SEM microstructures using ImageJ and MATLAB showed that at least two different levels of hierarchies are present in the microstructure for both cases, which are referred to as BHF stacks and micro-chains. From the experimental quantitative microstructure analysis, BHFs are found to be slightly better oriented (magnetic easy-axis direction in relation to the external field) at all scales for the electric and magnetic field processed composites compared to just the magnetic field processed composites. Magneto-electrohydrodynamics modeling of the polymer-particulate mixture predicts a similar behavior. Computational simulations are performed wherein particulates, subjected to both DEP forces resulting from an applied electric field, and magnetic dipole interactions in response to applied magnetic field, are allowed to form quasi-equilibrium structures before locking in a final structure to represent curing. Results from simulation confirms the finding on longer macro-chain formation similar to the experiment for the case of magnetic and electric fields compared to just magnetic field. Analysis of the microstructures from simulation also confirms that multiple levels of hierarchies are present in the composites’ microstructure for both cases. In future, quantifying the corresponding metrics at each level of hierarchy will help to better understand the microstructure and can be served as input to the model and also used to validate the model.