Tuesday  |  Salon 7  |  09:40 AM–10:00 AM

#16364, Applications of rheo-optics measurement of soft matters using a rheometer and a polarization imaging camera

Soft matter materials exhibit different deformation or flow behaviors from hard ones, such as metals, because the internal structure of soft matter changes depending on the deformation of flow. The internal structure includes the network structure of polymer materials and structures formed by the orientation of various materials, among others. For example, flow-induced orientation of polymers occurs during molding, and the orientation affects the properties of the molded items. Investigating such structural changes experimentally is very useful for not only the quality control of molded products but also elucidating the mechanism for complex phenomena in soft matter. Thus, it is important to analyze the associated structures to various phenomena.
The rheo-optics is an experimental method where the optical measurement or the observation is synchronously carried out with the rheological measurement. One important piece of information that can be measured with the rheo-optics is the birefringence, capable of verifying the molecule orientation and the sub-micrometer size structure in the soft matter materials. The results of these measurements can be directly compared with the rheological data. Therefore, the rheo-optics is a powerful tool to solve problems in the structure and dynamics of soft matter. Recently, we developed a new rheo-optics system with the high-speed polarization camera that can easily visualize two-dimensional birefringence and orientation angle distributions on the micron to millimeter order caused by deformation or flow of matter. It also enables the estimation of material properties, which are important for developing new materials and optimizing molding conditions.
This presentation introduces two study cases of rheo-optics measurement of cellulose nano fiber (CNF) suspensions and polymeric materials. In the case of CNF suspensions, we investigated the mechanism of CNF yielding behavior by a stress-ramp test. In the other case, we will show the results of DMA measurement of polymer solids. From this measurement, we succeeded in visualizing the dynamics of materials near the glass transition temperature and the relaxation phenomenon in the rubber region.

Andrew Bridges   Photron