Monday, 23 May 2005 - 11:30 AM

This presentation is part of: Inorganic and Organometallic Polymers I

Silsesquioxane based Inorganic Organic Hybrid Copolymers

E. Bryan Coughlin, University of Massachusetts Amherst, Amherst, MA

The ability to tune assembly processes of organic polymers and inorganic monoliths from the nano-scale to meso-scale remains a considerable challenge. To explore the competitive, or cooperative, effects of self-assembly in hybrid systems novel inorganic-organic random and block copolymers are being prepared to facilitate investigations of the inherent ability of one component in the hybrid systems to aggregate and thus direct the assembly of the other. Polyhedral oligomeric silsesquioxanes (POSS) are molecularly precise isotropic particles with average diameters of 1-2 nm. A typical T8 POSS nanoparticle has an inorganic Si8O12 core surrounded by eight aliphatic groups (eg. cyclopentyl or cycylohexyl) attached to the silicon vertices of the polyhedron promoting solubility in conventional solvents. The incorporation of POSS macromonomers in both semi-crystalline and amorphous polymers is readily achieved using a range of synthetic methodologies. Analysis of the copolymers using WAXD reveals that the pendant POSS groups off the polymer backbones aggregate and crystallize as nanocrystals. The limitation on POSS particle aggregation and crystallization due to their incorporation along the polymer backbone serves to limit crystallization to anisotropic shapes. The self-assembly process of ordering isotropic nano-scale sub-units into anisotropic layered structures will be discussed as a design strategy, a 'bottom-up' approach, for generating long range order in hybrid organic-inorganic copolymers.

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