Carlos R. López Barrón, a Ph.D. candidate in Chemical Engineering/Materials Science, will defend his thesis: "On the coarsening of immiscible polymer blends with cocontinuous morphology", on November 18th at 1:00 pm in Amundson Hall 116. Carlos is advised by Chris Macosko.
Below is an abstract of his thesis:
The coarsening of cocontinuous blends were studied using novel 3D imaging techniques and reheology. Laser scanning confocal microscopy coupled with differential geometry were used to obtain and analyze 3D images of cocontinuous fluorescently-labeled polystyrene/styrene-acrylonitrile copolymer blends. Algorithms to extract information of the size, shape (curvature) and anisotropy of the interface were developed. The time evolution of the size, curvatures and elastic modulus were monitored. From the analysis of the size and curvature, two regimes of coarsening were identified, namely, an early regime where the microstructure growth is linear and self-similar and a late regime where the rate of coarsening slows down and non self-similarity was observed. Similar to the interfacial area, the elastic modulus decreased during the coarsening process. A simplification to Doi-Ohta's model was proposed to quantitatively relate morphological and rheological changes during annealing of the blends. Good agreement was observed for blends with low interfacial tension in the late regime of coarsening.