Superparamagnetic Triblock/Fe2O3 Nanofibers
Department of Chemistry, University of Calgary,
Calgary, Alberta T2N 1N4 CANADA
This is an abstract
for a presentation given at the
Ninth
Foresight Conference on Molecular Nanotechnology.
There will be a link from here to the full article when it is
available on the web.
Block copolymers self-assemble in bulk forming various intricate nanometer-sized block segregation patterns.1 Block-segregated solids of diblock copolymers have been processed chemically in the past to yield nanofibers,2, 3, 4, 5 nanospheres,6 nanochannels in thin films,7, 8 inorganic nanoparticles in polymer matrices,9, 10, 11, 12 and photolithographic masks with nanometer-sized patterns.13 Linear triblocks AnBmCl, where A, B, and C denote different monomers, are far richer in block segregation patterns than diblocks. Despite this, there have been only a few reports of nanostructure preparation from block-segregated triblock solids. Here we report the preparation of polymer/Fe2O3 hybrid nanofibers from processing films of a triblock copolymer polystyrene-block-poly(2-cinnamoyloxyethyl methacrylate)-block-poly(t-butyl acrylate) or PS-b-PCEMA-b-PtBA. Also to be reported will be the superparamagnetism of the hybrid nanofibers and their alignment in magnetic fields.
The preparation involved the self-assembly of the blocks in thin films into concentric PCEMA and PtBA cylinders dispersed in the matrix of PS (A-->B of Scheme 1). The cylindrical structures were then locked in by photo-crosslinking the PCEMA shells (B-->C). Dissolving the films in THF yielded individual nanofibers with PS coronas, PCEMA middle layers, and PtBA cores (C-->D). Nanotubes with poly(acrylic acid)- or PAA-lined cores were obtained after cleaving the t-butyl groups from PtBA (D-->E). Producing Fe2O3 nanoparticles in the PAA cores yielded solvent-dispersible superparamagnetic block copolymer/inorganic hybrid nanofibers (E-->F).
Scheme I
References
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Abstract in RTF format 25,419 bytes
*Corresponding Address:
Guojun Liu
Department of Chemistry, University of Calgary
2500 University Dr., NW, Calgary, Alberta T2N 1N4 CANADA
Phone: 403-220-5343
Fax: 403-289-9488
Email: [email protected]
http://www.chem.ucalgary.ca/groups/gliu
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