Research

Our research is centered around using rheological, optical, and scattering techniques to probe the morphology of flowing liquids. For us, the interesting systems are those with structure, including high-molecular-weight polymers and block copolymers, as described below. We are also investigating other types of fluids with structure, including sol-gels and suspensions. 

Block Copolymers 

Copolymers are macromolecules that are made up of different chemical units bonded together to make one long chain. When the chemical units are arranged in long blocks, the polymer may undergo microphase separation; i.e., the like-chain blocks want to phase separate but are prevented from undergoing macroscopic phase separation by the covalent bonds that bind the parts together. The structures formed by these molecules are unique and can be exploited to make materials with desirable mechanical and chemical properties. One of our goals is to understand the flow mechanism of microphase-separated block copolymers. To probe the morphology of these flowing systems, we use small-angle neutron scattering on a flow cell and small-angle X-ray scattering on quenched samples. 

Nonlinear-Viscoelasticity  

Many researchers have noticed anomalous rheological behavior in high-molecular-weight polymer systems, but there is a great deal of controversy as to whether the observations are due to stick/slip failure at the walls of the flow cell or whether the response is an intrinsic fluid-flow property. These flow instabilities are important since they contribute to melt fracture, a phenomenon that affects processing methods in the plastics industry. We are studying model systems to try to understand the flow response of polymers. Our tools include rheology and flow birefringence. 

Selected Publications  

1. Morrison, Faith A., Drawing the Connections: Engineering Science and Engineering Practice," to appear, Chemical Engineering Education, Fall 2005.
2. Morrison, Faith A., "What is rheology anyway?" The Industrial Physicist, 10(2), April/May, 2004, pp 29-31.
3. Morrison, Faith A., Understanding Rheology (Oxford University Press, 2001), ISBN 0-19-514166-0.
2. A. Nakatani, F. Morrison, C. Jackson, J. Douglas, J. Mays, M. Muthukumar, and C. Han, Shear-Induced Changes in the Order-Disorder Transition Temperature and the Morphology of a Triblock Copolymer, Journal of Macromolecular Science-Physics Edit4ion, B35 (3/4), 489 (1996). 
5. P. Manjeshwar, F. Morrison, and J. Mays, Test of the Constitutive Hypothesis of Melt Fracture: Large Amplitude Step-Shear of Polyisoprenes, Proceedings of the XIIth International Congress on Rheology, Quebec City, Canada, August 18 23, 1996, A. Ait-Kadi, J. Dealy, D. James, and M. Williams, eds., 123. 
6. A. Nakatani, F. Morrison, J. Douglas, J. Mays, C. Jackson, M. Muthukumar, and C. Han, The Influence of Shear on the Ordering Transition of a Triblock Copolymer Melt, Journal of Chemical Physics, 104, 1589 (1996). 
7. F. Morrison and R. Larson, A Study of Shear Stress Relaxation Anomalies in Binary Mixtures of Monodisperse Polystyrenes, J. Polymer Science: Polymer Physics Edition, 30, 943 (1992).