Analysis of non-Newtonian liquids using a microfluidic capillary viscometer
Nimisha Srivastava1, Mark A Burns
1Department of Chemical Engineering, The University of Michigan, Ann Arbor, Michigan 48109, USA.
Analytical Chemistry
|March 1, 2006
Summary
A novel self-calibrating microfabricated capillary viscometer rapidly analyzes non-Newtonian power law fluids. This device accurately measures viscosity across a wide range of shear rates using minimal sample volume.
Area of Science:
- Materials Science
- Fluid Dynamics
- Analytical Chemistry
Background:
- Non-Newtonian fluids exhibit complex flow behaviors.
- Accurate viscosity measurements are crucial for material characterization.
- Traditional viscometers can be time-consuming and require large sample volumes.
Purpose of the Study:
- To develop and validate a self-calibrating microfabricated capillary viscometer.
- To enable rapid and accurate analysis of non-Newtonian power law fluids.
- To assess the device's performance with diverse fluid samples.
Main Methods:
- Utilized a microfabricated capillary viscometer for pressure-driven fluid flow.
- Measured viscosity by monitoring fluid velocity and calculating shear rate over time.
- Employed a self-calibrating system for enhanced accuracy.
Main Results:
- Successfully analyzed various non-Newtonian fluids, including polymer solutions (poly(ethylene oxide), hydrolyzed polyacrylamide, xanthan gum) and inks.
- Achieved viscosity measurements from 1-600 cP with shear rates from 5 to 1000 s⁻¹.
- Demonstrated rapid analysis (2-8 min) with minimal sample volume (<1 µL).
Conclusions:
- The microfabricated capillary viscometer offers a robust and efficient method for non-Newtonian fluid analysis.
- The device's capabilities are suitable for applications requiring quick, repeated measurements with limited sample volumes.
- Potential applications include quality control and manufacturing processes.
Related Concept Videos
01:17Viscosity
When water is poured into a glass, it falls freely and quickly, whereas if honey or maple syrup is poured over a pancake, it flows slowly and sticks to the surface of the container. This difference in the flow of different kinds of liquids arises due to the fluid friction between the liquid layers and the liquid and the surrounding material. This property of fluids is called fluid viscosity. In this example, water has a lower viscosity than honey and maple syrup.
The SI unit of viscosity is...
The SI unit of viscosity is...
01:27Viscosity
Viscosity is a property of fluids that measures their resistance to flow. It is influenced by factors such as the surface area of contact, the gradient of flow speed, and the fluid's viscosity constant, called the coefficient of viscosity. The coefficient of viscosity, also known as dynamic viscosity, is denoted by the symbol η. It determines the proportionality between the viscous force and the gradient of flow speed.Newton's law of viscosity states that the viscous force on a faster-moving...
01:19Viscosity of Fluid
Viscosity measures the resistance a fluid offers to flow and deformation. It results from internal friction between layers of fluid moving relative to one another. Dynamic viscosity, denoted by the Greek letter mu (μ), quantifies the force needed to move one fluid layer over another. For Newtonian fluids like water and air, the relationship between the shearing stress and the rate of shearing strain is linear, meaning their viscosity remains constant regardless of the applied stress.
01:27Types of Fluids
Fluids can be classified into Newtonian and non-Newtonian fluids based on their response to shear stress. Newtonian fluids have a linear relationship between shear stress and the shear strain rate, following Newton's law of viscosity. Their viscosity remains constant regardless of the shear rate, making their behavior predictable and easier to analyze. Common examples include water, air, oil, and gasoline.
In contrast, non-Newtonian fluids do not follow Newton's law of viscosity, and their...
In contrast, non-Newtonian fluids do not follow Newton's law of viscosity, and their...
01:18Newtonian Fluid: Problem Solving
Newtonian fluids exhibit a constant viscosity, meaning their shear stress and shear strain rate are directly proportional. This property ensures a predictable and stable response to applied forces, maintaining a linear relationship between force and flow. Examples include water, air, and light oils, consistently demonstrating this proportional behavior regardless of external conditions.
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...
01:19Capillarity in Fluid
Capillarity describes the movement of liquid in small spaces without external forces acting on it. The capillarity is driven by surface tension and adhesive interactions between the liquid and surrounding solid surfaces. This effect is often seen in narrow tubes, porous materials, and fine particles.
Surface tension is crucial to capillarity. It results from cohesive forces between liquid molecules at the liquid-air boundary, forming a skin that resists external forces. When the capillary tube...
Surface tension is crucial to capillarity. It results from cohesive forces between liquid molecules at the liquid-air boundary, forming a skin that resists external forces. When the capillary tube...