Channel Flow of Homogeneous Electrorheological Fluids

在这项研究中，基于液晶聚合物（lcp）的均相电流变（ER）流体在狭窄分离电极之间的压力驱动流动中进行了实验表征。这项工作的目的是在复杂的流动几何形状中发展对均匀内质流体的定量理解，以便评估在常规和微流体应用中使用该流体的技术可行性。项目范围包括三个部分：(1)LCP的合成，(2)LCP溶液ER行为的实验表征和定量机理建模，以及(3)LCP溶液在简单和复杂制备通道中的测试。聚异氰酸正己酯是通过活的、可逆的聚合反应合成的，可以得到不同分子量的单分散样品。通过实验表征了在剪切速率和电场强度范围内的phcp浓溶液的粘度，并用Doi先前开发的二维LCP流变性分子理论建立了模型。在圆入口通道中进行了恒流量下的稳态和瞬态压降测量。利用电子束光刻技术制作了一种覆盖图案的特殊微电极，通过电极的选择性通电，以规定的方式引导二维平面内质网流体流动。这项工作将允许，在50年的ER流体研究中，第一次从流体组分的性质中完成对ER行为的先验预测。这种预测能力将ER流体配方与ER设备设计联系起来，因此严格的工程分析可以确定使用均匀的ER流体可以实现ER设备估计潜在的数十亿美元市场的哪一部分。

Annette D. Shine, University of DelawareProposal #0085026Channel Flow of Homogeneous Electrorheological Fluids In this research, homogeneous electro-rheological (ER) fluids based on liquid crystalline polymers (LCPs) are characterized experimentally in pressure-driven flow between narrowly separated electrodes. The objective of this work is to develop a quantitative understanding of homogeneous ER fluids in complex flow geometries, in order to assess the technical feasibility of using the fluids in conventional and microfluidic applications. The project scope consists of three parts: (1) synthesis of the LCP, (2) experimental characterization and quantitative mechanistic modeling of the ER behavior of LCP solutions, and (3) testing of the LCP solutions in simple and complex fabricated channels.Poly(n-hexyl isocyanate) (PHIC) is synthesized by living, reversible polymerization to produce monodisperse samples various molecular weights. The viscosity of concentrated solutions of PHIC is experimentally characterized over a range of shear rates and electric field strengths, and modeled with a previously developed two-dimensional version of Doi's molecular theory of LCP rheology. Steady state and transient pressure drop measurements at constant flow rate are conducted in rounded-entry channels. Special micro-electrodes are fabricated by electron beam lithography in an overlay pattern in order to direct two-dimensional planar ER fluid flow in a prescribed fashion by selective electrification of electrodes. This work will allow, for the first time in 50 years of ER fluid research, the complete a priori prediction of ER behavior from the properties of the fluid components. This predictive capability links ER fluid formulation with ER device design, so that rigorous engineering analysis can identify which fraction of the estimated potential billion dollar market for ER devices can be realized using homogeneous ER fluids.