Alizadehgiashi Moien, Khabibullin Amir, Li Yunfeng, Prince Elisabeth, Abolhasani Milad, Kumacheva Eugenia
Department of Chemistry, University of Toronto , 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada.
Department of Chemical and Biomolecular Engineering, North Carolina State University , 911 Partners Way, Raleigh, North Carolina 27695-7905, United States.
Langmuir. 2018 Jan 9;34(1):322-330. doi: 10.1021/acs.langmuir.7b03648. Epub 2017 Dec 18.
Flow-induced alignment of shape-anisotropic colloidal particles is of great importance in fundamental research and in the fabrication of structurally anisotropic materials; however, rheo-optical studies of shear-induced particle orientation are time- and labor-intensive and require complicated experimental setups. We report a single-droplet oscillatory microfluidic strategy integrated with in-line polarized light imaging as a strategy for studies of shear-induced alignment of rod-shape nanoparticles. Using an oscillating droplet of an aqueous isotropic suspension of cellulose nanocrystals (CNCs), we explore the effect of the shear rate and suspension viscosity on the flow-induced CNC alignment and subsequent relaxation to the isotropic state. The proposed microfluidic strategy enables high-throughput studies of shear-induced orientations in structured liquid under precisely controlled experimental conditions. The results of such studies can be used in the development of structure-anisotropic materials.
流动诱导的形状各向异性胶体颗粒排列在基础研究和结构各向异性材料的制造中具有重要意义；然而，剪切诱导颗粒取向的流变光学研究既耗时又费力，且需要复杂的实验装置。我们报告了一种与在线偏振光成像相结合的单滴振荡微流体策略，作为研究棒状纳米颗粒剪切诱导排列的一种策略。利用纤维素纳米晶体（CNC）的各向同性水悬浮液的振荡液滴，我们探究了剪切速率和悬浮液粘度对流动诱导的CNC排列以及随后向各向同性状态弛豫的影响。所提出的微流体策略能够在精确控制的实验条件下对结构化液体中剪切诱导的取向进行高通量研究。此类研究结果可用于结构各向异性材料的开发。
