Zimra Payvand Ahdout RHS Õ07
(with Christopher Pynn, Half Hollow Hills High School West)
Thin films of EVA or PE and dPS were spun cast onto Si
wafers and crystallized in supercritical carbon dioxide at pressures and
temperatures corresponding to the density fluctuation ridge or thermally
annealed using standard protocols. The morphology composition and melting
points of the films were studied using scanning force microscopy and imaging
time-of-flight secondary ion mass spectrometry as function of film thickness
and homopolymer concentration. The results showed that exposure to scCO2
produced highly crystalline films. Furthermore, in contrast to the thermally
annealed films, the homopolymer was fully incorporated into the crystalline
phase. The surface morphology of the films after crystallization showed either
island or hole structure, depending on the relation between the film thickness
and the lamellar height.