Innovative use of a powder rheometer
How would you use a powder rheometer? – To analyze “smart material” and self-healing material was the answer given by John F. Brady from the California Institute of Technology – in short CALTECH.
The innovative answer given by Mr. Brady was honored with a powder rheometer from Anton Paar at the last Annual Meeting of the Society of Rheology. Since Mr. Brady is the executive officer of Chemical Engineering at CALTECH his answer naturally has to do with chemistry. The focus of Brady’s research combines the rheology and dynamics of colloidal suspensions and the behavior of active matter, which consists of entities that can move by themselves.
By using a powder rheometer Mr. Brady analyzes the rheological behavior of dense, active colloidal particles or “active powders” during a chemical reaction. This has significant implications for technology and science.
For Mr. Brady the creation of smaller, simpler and more efficient actuators is one crucial application. Actuators are so-called “smart materials”. They can change their properties in response to external stimuli or to their environment. In the functioning of a device the actuators can play a significant role but they are hard to fabricate. To create “ideal” actuators chemists need to know about the generated pressure, the response time to environmental change, the optimal concentration, etc.
Rheological analysis is also relevant when it comes to self-healing materials. Forces and motion generated by active particles can be analyzed in order to design self-healing material. When a material’s surface is ruptured the particles are exposed to another chemical environment and turn on their activity. By moving to the rupture the active particles can plug the leak.
The powder rheometer Mr. Brady won at the last Annual Meeting of the Society of Rheology supports his research and gives valuable insights into a new frontier of material science and fluid dynamics.
With the new Powder Cell from Anton Paar, the modular compact rheometers of the MCR series become fully functional powder rheometers. This setup can be used to characterize the flow behavior of all kinds of granular materials – from the finest powders to larger particles like rice grains.