The flexure-based microgap rheometer (FMR)
The flexure-based microgap rheometer (FMR)
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DOI：
10.1122/1.2357190
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发表时间：
2006-11-01
影响因子：
3.3
通讯作者：
McKinley, Gareth H.
中科院分区：
文献类型：
--
作者：
Clasen, Christian;Gearing, Brian P.;McKinley, Gareth H.
本文介绍了一种新型微流变仪的设计和结构，该微流变仪的设计目的是为了便于对具有微米尺寸间隙的小样品体积(1-10亩L)的复杂流体进行粘度学研究。基于挠曲的微间隙流变仪(FMR)是一种剪切速率控制的LED设备，能够测量平面Couette结构中的剪切应力，其间隙在1到200微米之间。白光干涉测量和使用压电步进电机的三点纳米定位平台被用来控制由玻璃光学平板构成的上下剪切面的平行度。复合挠性系统用于将流体样品测试单元固定在连接到“尺寸式”电机的驱动弹簧和独立的传感器弹簧之间。使用感应式接近传感器来检测传感挠性件中的位移。通过长距离工作的视频显微镜，可以方便地通过光学接触透明剪切面，监控缝隙中的结构演变。这一配置使我们能够确定复杂流体在50年剪切速率下的微间隙相关流动行为。我们通过表征典型微结构食品(蛋黄酱)在8到100微米和10到1500帕压力范围内的复杂应力和依赖间隙的流动行为来展示FMR的能力。我们将乳状液的微观结构与间隙相关的流变学响应与长时间剪切引起的材料变化相关联。(C)2006年流变学学会。
We describe the design and construction of a new microrheometer designed to facilitate the viscometric study of complex fluids with very small sample volumes (1-10 mu l) and gaps of micrometer dimensions. The flexure-based microgap rheometer (FMR) is a shear-rate-control led device capable of measuring the shear stress in a plane Couette configuration with directly controlled gaps between I and 200 mu m. White light interferometry and a three-point nanopositioning stage using piezo-stepping motors are used to control the parallelism of the upper and lower shearing surfaces, which are constructed from glass optical flats. A compound flexure system is used to hold the fluid sample testing unit between a drive spring connected to an "inchworm" motor and an independent sensor spring. Displacements in the sensing flexure are detected using an inductive proximity sensor. Ready optical access to the transparent shearing surfaces enables monitoring of the structural evolution in the gap with a long working-distance video microscope. This configuration then allows us to determine the microgap-dependent flow behavior of complex fluids over 5 decades of shear rate. We demonstrate the capability of the FMR by characterizing the complex stress and gap-dependent flow behavior of a typical microstructured food product (mayonnaise) over the range of gaps from 8 to 100 mu m and stresses from 10 to 1500 Pa. We correlate the gap-dependent rheological response to the microstructure of the emulsion and changes induced in the material by prolonged shearing. (c) 2006 The Society of Rheology.