Infoscience

Thesis

Templating Approach Towards Lamellar Carbon Nanomaterials from Oligo(phenylene) Amphiphiles

Templating approaches based on the self-assembly of block-copolymers represent a powerful tool for the preparation of ordered carbon-containing nanomaterials. Combining such strategies with the use of well-defined amphiphilic precursors with sp2-carbon-rich cores provides a way to better tailor carbon nanostructures with predetermined morphologies. This thesis, therefore, explores a soft templating approach using the self-assembly of linear poly(ethylene oxide)-substituted oligo(phenylene) amphiphiles as both a template for the formation of lamellar structures and sp2-carbon-rich source for the synthesis of ordered carbon nanostructures. Our investigations showed that a series of such coil-rod-coil molecules with different numbers of phenylene units in their core exhibited a rich polymorphism of tilted lamellar phases in bulk over a wide range of temperatures. We found that the self-assembly of the oligo(phenylene) rods into lamellar domains induced nanoscopic confinement of the poly(ethylene oxide) chains, resulting in a significant increase of their melting point to temperatures of up to 228 °C. Moreover, the cooperative self-assembly of the hexa(phenylene) amphiphile with sol-gel aluminosilicate precursors enhanced by solvent evaporation, and the subsequent carbonization of the obtained mesophases at 600 °C successfully furnished lamellar carbon-aluminosilicate nanocomposites. Following this approach, macroscopically oriented films of nanocomposites were prepared on a substrate by a shearing technique. Detailed structural characterization of the film morphology revealed lamellae with macroscopic order, an ¿edge-on¿ orientation relative to the substrate, as well as periodicities on the order of the molecular length scale. Furthermore, an ordered lamellar porous carbon was prepared by successfully etching the aluminosilicate phase, giving rise to a porous material with a large surface area that was appeared to be promising for hydrogen storage applications.

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