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dc.contributor.authorSato, Junen_US
dc.date.accessioned2007-03-27T18:18:48Z
dc.date.available2007-03-27T18:18:48Z
dc.date.issued2006-10-30en_US
dc.identifier.urihttp://hdl.handle.net/1853/14044
dc.description.abstractA new microrheology set-up is described, which allows us to quantitatively measure the transient rheological properties and microstructure of a variety of solvent-responsive complex fluids. The device was constructed by integrating particle tracking microrheology and microfluidics and offers unique experimental capabilities for performing solvent-response measurements on soft fragile materials without applying external shear forces. Transient analysis methods to quantitatively obtain rheological properties were also constructed, and guidelines for the trade-off between statistical validity and temporal resolution were developed to accurately capture physical transitions. With the new device and methodology, we successfully quantified the transient rheological and microstructural responses during gel formation and break-up, and viscosity changes of solvent-responsive complex fluids. The analysis method was expanded for heterogeneous samples, incorporating methods to quantify the microrheology of samples with broad distributions of individual particle dynamics. Transient microrheology measurements of fragile, heterogeneous, self-assembled block copolypeptide hydrogels revealed that solvent exchange via convective mixing and dialysis can lead to significantly different gel properties and that commonly applied sample preparation protocols for the characterization of soft biomaterials could lead to erroneous conclusions about microstructural dynamics. Systematic investigations by varying key parameters, like molecular structure, gel concentration, salt concentration, and tracer particle size for microrheology, revealed that subtle variations in molecular architecture can cause major structural and microrheological changes in response dynamics. Moreover, the results showed that the method can be applied for studying gel formation and breakup kinetics. The research in this thesis facilitates the design of solvent-responsive soft materials with appropriate microstructural dynamics for in vivo applications like tissue engineering and drug delivery, and can also be applied to study the effect of solvents on self-assembly mechanisms in other responsive soft materials, such as polymer solutions and colloidal dispersions.en_US
dc.format.extent3431927 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.publisherGeorgia Institute of Technologyen_US
dc.subjectComplex fluidsen_US
dc.subjectMicrorheologyen_US
dc.subjectMicrofluidicsen_US
dc.subjectStimuli-responsiveen_US
dc.subject.lcshTransients (Dynamics)en_US
dc.subject.lcshSmart materialsen_US
dc.subject.lcshRheologyen_US
dc.subject.lcshMicrofluidicsen_US
dc.subject.lcshComplex fluids Analysisen_US
dc.subject.lcshColloidsen_US
dc.titleTransient Rheology of Stimuli Responsive Hydrogels: Integrating Microrheology and Microfluidicsen_US
dc.typeDissertationen_US
dc.description.degreePh.D.en_US
dc.contributor.departmentChemical Engineeringen_US
dc.description.advisorCommittee Chair: Victor Breedveld; Committee Member: Andreas S. Bommarius; Committee Member: J. Carson Meredith; Committee Member: L. Andrew Lyon; Committee Member: William J. Korosen_US


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