CHED 729 |
| High temperature dynamic light scattering (DLS) and cloud point measurements were used to study polymer blends composed of polystyrene (PS), polybutadiene (PB), and a PS-PB diblock copolymer. The copolymer acts as a surfactant potentially leading to the formation of a bicontinuous microemulsion (BME). Measurements as a function of scattering angle were taken over a temperature range of 180°C to 75°C. Intensity autocorrelation functions for all polymer compositions were fit using a double exponential function and were combined with zero-shear viscosities to determine dynamic correlation lengths. Two distinct density fluctuations were observed. The dynamic correlation lengths from the fast mode for the binary and 4% diblock blends diverge near their cloud point temperatures as the samples phase separate. The 8%, 10%, and 12% diblock blends have dynamic correlation lengths that do not diverge when temperature is lowered suggesting the presence of a BME similar to research presented in the literature. |
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Undergraduate Research Poster Session: Polymer Chemistry
11:00 AM-1:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A, Poster
Division of Chemical Education |