|کد مقاله||کد نشریه||سال انتشار||مقاله انگلیسی||ترجمه فارسی||نسخه تمام متن|
|5518461||1543966||2017||5 صفحه PDF||سفارش دهید||دانلود کنید|
A 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.
Journal: MethodsX - Volume 4, 2017, Pages 305-309