Shear rheological characterization of gel healing response and construction of rheo-PIV system
Thermo-reversible gels are solvent-filled 3D networks of polymer chains interconnected by physical (transient) crosslinks. On applying a high shear stress, the crosslinks are broken and these gels show a typical stress-strain behavior due to cohesive fracture of the gel. When heated above a critical temperature and cooled back to room temperature, all the crosslinks are re-formed. Interestingly, partial to full recovery of broken crosslinks is also observed by simply letting the gel stand at room temperature. In this study, the fracture and healing behavior of a model acrylic triblock copolymer gel has been characterized by shear rheometry. A mathematical model has also been proposed to better understand the mechanics at the molecular level and predict the healing time of a system. A rheo-PIV system was built as part of the project, to observe and confirm the bulk healing process in situ. Spontaneous self-healing behavior has immense potential in controlled drug delivery systems, coatings, food and various other applications.
Erk, Purdue University.
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