Mechanics of Soft Matter: Rheology

Soft matter comes in many forms and includes polymeric materials, suspensions, emulsions, foams, gels, and living tissue. These materials are characterized by being easily deformed and possessing internal relaxation time spectra. They are viscoelastic with responses that are intermediate between purely viscous liquids and perfectly elastic solids. This course provides an introduction to the subject of rheology, which concerns the deformation and flow of complex liquids and solids. Rheological testing is aimed at determining the relationships between the applied stresses in these materials and the resulting deformations. These are characterized by material functions, such as viscosity (shear and extensional), moduli, and compliances. These functions reflect the microstructure of the material being tested and microstructural models of polymers (single chain theories and reptation-based models), suspensions, emulsions, and foams will be presented. Experimental methods to measure materials subjected to both shearing and elongational deformations will be described. Many soft matter systems are influenced by interfacial phenomena (foams, emulsions, thin films in the human body) and interfacial rheological techniques will be discussed. Advanced undergraduates register for 170X; graduates register for 470.