Doctor of Philosophy (PhD)
This research seeks to understand the structure and shear responses of poly(ethylene oxide)-Laponite nanocomposite hydrogels and to relate the macroscopic physical properties to the nanoscopic structural changes. Understanding that relationship is necessary, in order to tailor material properties to specific applications. Information on the structure at rest on multiple length scales was obtained by combining microscopic and neutron scattering techniques. The structural changes that occur in response to a shear field were explored using rheology and neutron scattering. These structures were examined as a function of polymer molecular weight, polymer and clay concentrations, and sample preparation method. While the sample preparation method had no significant effect on these gels, the other two parameters were found to strongly influence the shear behavior of the systems. It was found that the dynamical behavior of these gels is controlled by the ability of a polymer chain to bridge clay platelets, which is influenced both by the length of the polymer and the clay and polymer concentrations.
Document Availability at the Time of Submission
Secure the entire work for patent and/or proprietary purposes for a period of one year. Student has submitted appropriate documentation which states: During this period the copyright owner also agrees not to exercise her/his ownership rights, including public use in works, without prior authorization from LSU. At the end of the one year period, either we or LSU may request an automatic extension for one additional year. At the end of the one year secure period (or its extension, if such is requested), the work will be released for access worldwide.
Loizou, Elena, "Shear Responses of Poly(ethylene oxide)-Laponite Nanocomposite Hydrogels" (2007). LSU Doctoral Dissertations. 2694.