(43c) Confinement-Induced Morphologies in Electrospun and Templated Block Copolymer/Polymer Derived Ceramic Precusor Nanocomposites

Block copolymers (BCPs) self-assemble into a variety of ordered microstructures on the nanometer scale. An additional level of complexity is imposed upon the self-organization when the BCP is encompassed within confining surfaces on the length scale (i.e nanometers) of the domain sizes of the micro-phase separated morphology. Using co-axial electrospinning and template wetting, we have explored the confined-assembly of amphiphilic structure directing BCP/polymer derived ceramic (PDC) precursor nanocomposites, which exhibited bulk two-dimensional hexagonal and lamellar morphologies. Continuous electrospun nanofibers were generated by enveloping the BCP/PDC nanocomposite core in a sheath of a high glass transition polymer. The resulting nanofibers exhibited helical and stacked toroidal mesostructures compared to a bulk hexagonal morphology. Nanorods of the BCP hybrids with a lamellar bulk morphology were also obtained via template wetting in aluminum oxide nanopores. These templated nanorods displayed concentric ring morphology under confinement. These confinement strategies offer the ability to develop continuous nanofibers and nanorod arrays of high-temperature, non-oxide ceramics with potential applications in catalysis, sensing, and separations.