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Session L36 - General Poster Session II.
POSTER session, Wednesday morning, March 22
Exhibit Hall, MCC

[L36.128] Sporadic Nucleation and Growth in the Microphase Separation Process of an I2S Miktoarm Star Block Copolymer and its Blends with Homopolymer

Lizhang Yang, Darrin J. Pochan, Samuel P. Gido (Polymer Science and Engineering Department, University of Massachusetts, Amherst, MA 01003), Stergios Pispas, Kunlun Hong, Jimmy W. Mays (Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL 35294)

A selective solvent and annealing study was done to investigate the morphology behavior of an I2S miktoarm star block copolymer and its blends with homopolyisoprene. Casting from cyclohexane, a selective solvent for polyisoprene, the neat star shaped I2S block copolymer only partially microphase separated, and formed a unique layered morphology inside a homogeneous media. During annealing, the layered phase and the homogeneous phase both transformed into a randomly oriented worm morphology. The path of this transformation is different depending on whether the starting state is layered or homogenous. The I2S/homopolyisoprene blend formed a mostly homogeneous phase after casting from cyclohexane. Annealing produced slow microphase separation which was observed at various stages by TEM. Based on these observations, a sporadic nucleation process of microphase separation is proposed.

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