文章基本信息

标题：Determination of the critical values of flow parameters characteristic of the alignment of cylindrical nano-objects in suspensions
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作者：Alexander A. Loshkarev ; Maria F. Vlasova ; Natalya I. Sapronova 等
期刊名称：MethodsX
印刷版ISSN：2215-0161
电子版ISSN：2215-0161
出版年度：2017
卷号：4
页码：305-309
DOI：10.1016/j.mex.2017.09.002
语种：English
出版社：Elsevier
摘要：Graphical abstractDisplay OmittedAbstractA method for determining the critical values of the flow speed and the flow constriction degree characteristic of the alignment of cylindrical nano-objects in a flowing suspension is proposed. Previously, the alignment process of cylindrical nano-objects in suspensions was investigated by using birefringence of the polarized light and the small-angle X-ray scattering. While both methods are suitable for measuring the alignment degree of cylindrical nano-objects in suspensions diluted down to low concentrations, they are restricted for the application to undiluted concentrated suspensions because of non-transparency and multiple scattering of X-rays. In addition, the use of the second method requires an expensive synchrotron equipment. We present a simple and faster method based on the direct ultrasound attenuation measurements of longitudinal viscosity of a suspension containing cylindrical nano-objects, which decreases monotonically, approaching its asymptotic value with increase in the flow speed and the flow constriction degree. The principle and advantages of the proposed method are as follows:•The cylindrical nano-objects align along an accelerated flow at overcritical values of the flow speed and the constriction degree.•The critical values correspond to the state of a suspension possessing viscosity close to the asymptotic value.•The method is applicable to undiluted concentrated suspensions, including opaque ones.
关键词：Ultrasound attenuation;Longitudinal viscosity;Suspension;Cylindrical nano-objects;Alignment;Critical parameters